# The Anatomy Of A Spinning Tunnel



## zombietoxin

Hi!

My first post to your fine forums and I thought I'd share a project of mine that has intrigued me for quite a while.

First though I want to make it clear that I am not an engineer or similar big-brain type, so what I am showing you comes with no claims to safety or integrity. If you are building one of these for friends, family or anyone else to use you better think twice about their safety and your liability!

So... I've seen all the tunnels on the web and a few personaly in action and I think the effect is really neat and memorable. Naturally I wanted one of my own! So I set about the study of what other DIY'ers have done only to find they either fall short in the intergity or durabilty areas. I decided to build mine as a professional would- built to last.

Little did I know what I was getting into...

Math. Math, math, math and more math! My fifth grade teacher was right! That stuff is everywhere! For the DIY'er (who is likely making things from scavenged parts) it's particularly important to understand gear ratios, as this knowledge will allow you to interchange whatever size parts you may come across.

I decided I would make the whole thing out of steel because its durable and I own a welder. I might have used aluminum for some things but I do not own a spool gun. I then drew up the plans for the rest using Corel Draw software. It's not really made for CAD design, but it did the trick for me. I'm sure you could use google sketch-up even more effectively- and its free. It was really tricky figuring ALL the little aspects out before starting, but I'm sure I saved time and money.

So first I needed the tunnel rings. I chose 1" square tubing because I am familiar with it and being square, it will roll nicely on the tunnel wheels. I have no ability to bend the rings properly so I went to a machine shop and had them make 5 for me. Not cheap- but they came out perfectly round and symetrical! They are 9' O.D.

Next was the bridge. WOW, definitely the hardest math! There are places on the net that have engineering calculators that will help you understand loads and load bearing properties of metal beams, but it still ain't not cake walk. Moment of Inertia- remember that. So I decided on the size and shape I thought would hold up under the worst case senario, and plunked down the cash- ouch! Turns out I own a lot more beam than maybe necessary, but I'm happy all the same. What I could never get a straight answer on was how the railings added to the load bearing capacity of the bridge beams. You know the railings act as a truss and provide additional support. Yeah... if you figure that out- 'splane it to me.

The rest of it was just a lot of square and right angle steel, misc brackets, and doo-dads...

Pictures or it didn't happen!

The rough stuff:

The rings, partially assembled bridge, and partially assembled rollers










The rings and bridge up on their feet










My cohort welding stuff and the rollers underneath.

I found the roller wheels on ebay pretty cheap. I think I'd want wheels somewhere between 6" - 10", and again it doesn't really matter the size as long as you can calculate gear ratios. You need to know the diameter of the tunnel rings, the diameter of the rollers, the diameter of the drive shaft sheave (pully), the diameter of the motor sheave and the output RPM of the motor. Your end calculations should put the tunnel RPM at around 6 - 12 RPM. Personally I ended up at about 6 and like the results a lot. If you go too fast the motion becomes blurry to the human eye and you lose the disorienting effects.










A good shot of the basic skeleton. As for the rollers- I decided that on one side they would be free spinning and on the other side they would be locked together in order to distribute the motion to all rings and prevent any twisting from ring section to ring section. This side is where I mounted the drive motor.










To be continued.....


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## zombietoxin

The motor. IMO you must use a gear motor and it must be rated for continuous use. Also because I wanted to keep it simple I needed one that would run on regular 110VAC. Finding a used one that met all that took me a while... but ebay provideth! And for less than 1/6th the new price! I've seen some debate about horse power necessary and I suppose it really depends on how you make your tunnel. I know for a fact that this one, even thought it rolls VERY freely (and quietly, I might add!) takes a 1/2 to 1/3 HP to get the job done without any strain. I also know for a fact that a 1/12 HP gear motor will not start the tunnel by itself.










OMG.. the sewing.... Need I say more? It takes a LOT of material to cover the bones! Again, IMO you better use a fire rated material! Duvetyn (doov-teen) aka commando cloth is a great choice. Be aware that they make different weights- I bought the lightest- 8oz. I also used velcro to attach it to the rings- ugh! more sewing!










Getting close!










To be continued...


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## Warrant2000

That is phenomenal! I hope you are doing the haunt right where the tunnel is, unless you have some tricky way to move it?


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## tot13

WOW! Just WOW! We built a vortex tunnel last year with Toktorill's help and design, but it looks like you could build these things to sell. Very professional looking and I'm very anxious to see it in action.


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## RoxyBlue

This is one ambitious project


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## scream1973

I'm anxious to see your breakdown of costs involved .. and also Storage?


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## samhayne

Niiice... would love to build one, but lime scream mentionned i cant afford storage for this one.

Thanks for the detaileds pictures...looks great


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## PirateLady

Looks like alot of work was put into this one. I know the tots will enjoy this one. Great job.


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## samseide

This thing is amazing! Also, what a great space you have for building props! Wish I had that much room!


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## Toktorill

Wow, this is one of the nicest looking tutorials on a VT I have ever seen- and believe me, I've seen a few! 

Hmm, so many questions, where to begin! Could you ballpark the cost a little more? What kind of haunt is this going into? Do you have a theme? Other props? Website?

Welcome to Hauntforum!


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## zombietoxin

Hello again, and thanks for the kind words!

There is more to come I promise, but it has been insanely hot- around 102 degrees in the warehouse- so I haven't been in there much (I'm hiding under my rock!).

I'm also working on a video do you can see it spinning. 

I'll be back....


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## zombietoxin

Ok, a bit more to share...

Well, I've been told a man has got to know his limitations- well, dressing a vortex in fabric may well me mine!

As you can see in this pic- the power of the vortex is ever-present! It's power sucks at the world around it whether it is running or not! Just look at the fabric being sucked inwards! Thats a 3'-4' inward curve- no matter how tight (or loose!) I pull it...










Now you might be wondering what the big deal is... Well-










It's dragging the bottom of the bridge! Arrg! That little miss calculation set me back a couple days trying to remedy it, and ended up with me raising the bridge two inches.

But that's not my real bane.. its the fabric! Damn stretchy fabric! Put it on, take it off, modify the size, put it on, take it off, modify the size! Wow, I was going batty and finally went from a one-piece fabric to a two-piece, but still had trouble getting everything to line up right. It's still not perfect but nothing drags or rubs and I can live with a few wrinkles for a while. I'll probably tackle it again after everything else is finished. FABRIC!

So I used 1" adhesive backed hook on the rings and 1.5" sew on loop on the fabric. That works really well (except for the stretchy fabric part).

Here's some important things I learned: even high quality velcro has shrinkage issues. The stuff is REALLY sticky and as I was applying it to the rings I thought -WOW thats never comming off! Well, two days later I walk through the warehouse and see about 50% of it hanging down. I was stunned considering how tacky it was. After some investigation and debate we decided the heat caused the material to shrink slightly and pull away from the rings. The velcro hook-side I used DOES NOT stretch so it had no choice but to pull away after shrinking. Luckily the solution was simple: cut it in two or three foot lengths and stick it back up. The stuff is so sticky it held the second time just like the first, and hasn't budged once even after repeatedly removing the fabric- good stuff.

The other important thing is that because the fabric piece was so big I couldn't get it to fit through my wifes sewing machine so that I could attach the middle peice of loop velcro. This meant I had the use adhesive to attach it- which worked great (btw Goop Automotive adhesive blew away E6000 adhesive- for this use anyway), buuuut the glue hardens and changes the stretchiness of the fabric in that area! Long story short- the fabric wouldn't fit now- too short in the middle! Thats why I had to cut it into two peices and sew the velcro on... ugh...

A shot of the velcro-










If you are wondering why there is white paint on the fabric- thats how I marked the position of the velcro to be attached- it worked pretty well.

Here are a few more pics:


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## zombietoxin




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## zombietoxin

So there are a lot of pics of the roller wheels. I think they speak for themselves, but if you have questions I'll try and answer them.

Some of the more important things I learned- the wheels I bought all had bearings in them which was great for the idler side- no additional bearings needed. But for the drive side- the wheels needed to be locked to the axle- hence the bars welded to the axle and bolted to each wheel. You may or may not end up with that kind of setup. Then the axle needed to ride on bearings so I bought "pillow blocks" which is the real name for mountable bearings. Finally, the axle itself must be "cold-rolled steel rod" in order to fit through the bearings smoothly and tightly. Hot rolled steel rod WILL NOT work.

What is still missing from the pictures is the black light fixtures and the Emergency Stop buttons on each end. (E-stop switch is the common name for those big round, red stop buttons.)

So to answer some questions-

The unit can be unbolted down to a storage size of about 20' long X 9' wide X 2.5' High and has a gross weight of around 1000 lbs I am guessing.

When unbolted all the way the single heaviest piece will be around 350 lbs (one bridge beam with bracketing, lights, etc.). No cake walk my friends.

I plan on moving it in three pieces- the whole bridge, the whole tunnel and the roller assembly under it all. Of course I have a forklift so...

All of this is/was for pro haunt. Unfortunatly (?) it will not be until 2011. We delayed our website launch for this reason until first quarter 2011. It will be zombietoxin.com. I have a few other goodies I have been tinkering with, but due to the heat I have not worked on them much, since there is no rush. I HAVE been eagerly peeping YOUR skills though and taking notes. You people are awesome and I'm glad I've found such a nice place to share.

Down to the costs....

Well, you know this wasn't cheap. I'm not bragging- trust me I wish it could be done for less, which really brings up the subject of- if you're going this far, why not just buy one?. I budgeted $2800. I blew past that pretty quickly, mostly due to improvements not originally planned but there were a few do-overs that I can subtract for a more realistic price. So here it is in a nut-shell:

Ring fabrication and machine shop: $700
I think I could get it done with some of my own work involved next time for about half that.

Duvtyne fabric, flourescent paint, netting (additional safety measure to hand rail): $315
These guys were the cheapest Duvtyne: http://www.onlineeei.com/fabrics.cfm

Plywood: $75

Roller wheels, pillow blocks, sheaves, motor: $380

Steel, fabricated roller wheel brackets: $1880

Black lights, wiring, conduits, switches, bolts, nuts: $250

Total: $3600

And I still plan on adding mirrors at both ends to increase the illusion, so that would probably run another $4-500.

Whats not included is there is equipment it took to fabricate it and any time compensation. I am lucky to have ample amounts of both on hand.

I don't own a camcorder- yet, so no video just yet. I still need to paint it anyway and install the lights, so I'll just wait until then to shoot it and post it in motion.

-Rob


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## kprimm

That tunnel is very impressive, but alot of work and money. I would not have enough roomm to set one up. Looks like yours will be awesome. Good luck on the rest of it.


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## tot13

Thanks for posting more pics; it's a pleasure to see the progress of your VT. I can appreciate the unplanned mods during assembly, but no one would know they existed because of the seamless way you've handled them.

Yeah, the estimated price range of $4K is out of reach for most of us, but that's really not a bad price for the amount of use (and reactions) that you'll get out of this. You'll probably get several years use out of it with only minor maintenance, and with the way you've built it, much of it will never have to be replaced. But back to the "out of reach" part, anyone interested in building a VT could learn a lot from your experience - and likely find some cheaper substitutes for some of the materials. As for you, your learning curve will go way up if you ever decide to build another VT.

I was disappointed to see that you're from Kansas - nothing against Kansas, but if that's where your haunt will be, that's a bit too much of a road trip for me. However, please let us know when your website will be up. Congrats to you (enviously, lol) on a great prop!


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## zombietoxin

Hi. Well I Finally got around to finding a camcorder to film this thing in action. I apologize for the poor low-light image quality in advance, but rest assured it is nice and bright in person. I think I may re-position the black lights slightly so they can cast more UV directly up... these things never seem to be finished, do they?

See it here-


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## mickkell

WOW,that is way cool.That is on my to do list,but not so expensive for my home haunt.Thanks for the great toot!


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## Warrant2000

Fantastic job, construction and execution. You're tot's will be thrilled!


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## zombietoxin

So, now that I've been through this from beginning to end I can see the possibility of making them for home haunts at a much reduced cost. 

However, I still feel strongly that safety must come first over cost, and that would primarily fall on the bridge and railing construction. I feel wooden construction is very suitable if done properly, but as I have no engineering background I cannot say exactly how it should be done. My take on it is like this- 20' seems short to anyone who builds them- thats why we end up putting mirrors on the end, so the thrill can go on and on! But to the unsuspecting guest 20' can seem like an eternity! Sooo- in the interest of safety, why not shorten the bridge slightly to reduce the load AND add mirrors to the ends? 

I honestly feel that everyone would get what they want out of that situation. Yes mirrors can be costly (we're talking plexi-mirror here), but I think that there are cheaper alternatives- namely build your own. I researched DIY mirrors and came up with the basic elements that put the cost of a 4'x8' mirror at around $50-$70 each. Thats the mylar film (optical grade!) + clear mylar overlay to protect the film from damage and a smooth backing material- either 1/4" masonite or 1/8" abs plastic sheeting.

This approach would also get you a much smaller storage foot print, as I am thinking a 12' bridge + mirrors = awesome thrill for the kids, yet much easier to store!

As for the rest- well, as long as it doesn't fall on their heads just about any approach is going to get results. For cost effective elegance I really like Toktorill's PVC construction and overhead drive. This seems to keep the bridge lower to the ground, which means fewer steps or lower ramp angle. This also seems to take some of the burden of having perfectly round rings out- again making things cheaper and simpler.

But, if you are going for the under-carriage approach, you WILL need to make the rings dang close to perfectly round and without any bumps from connectors or the like. Otherwise it will vibrate itself apart. Doing this part right, imo, will cut down on other demands and headaches. The plywood rings method is pretty good for this, and can be broken down for storage if built right. If, however, you are a nut like myself and thrill to the challenge- making one from steel with as much precision as you can muster, well then here's my opinion. Make them from square tube aluminum if you can. And if storage is an issue, cut the rings in half after fabrication and fabricate rounded truss plates to bolt the halves together- two on each joint (one on each side). Truthfully, there is nothing on the rings structure that NEEDS to be welded- it could all be assembled with brackets and bolts.

Here's a secret that the fabricators told me after they were done. First though, let me tell you about the fabricators- their shop was impressive. ALL manner of fabrication and even CNC , laser and water cutting and milling stuff. The foreman told me they regularly do jobs for the aerospace industry and NASA on occasion. Now all that being said, I was expecting this job to be a slam-dunk, one eye closed job... Not. Other than them being late on completion by 5 hours- as I waited- in my non air conditioned truck, I was most surprised that it took 3 and sometimes 4 guys to get the rings built! But build them they did, and they were amazingly true and round.

The problem and the secret. The problem lies in that the circumference of a 9' ring is around 30' and square tubing comes in 24' lengths. This presents a challenge if you are shooting for perfection. The secret, that they didn't do, but would now if they had to do it again, is to weld two pieces together BEFORE putting them through the roller so that they don't have to connect them after. I sort of thought that's how they were going to do it in the first place, but who am I to question the experts? 

And finally, in the way of prominent items, is the motor. I think if my tunnel weighed half of its current weight, that 1/12th hp gear motor I had would have worked fine. A 1/6th would have been even better. The point is those motors are pretty small ( around 12" L x 8"W x 8" H on average), are all over ebay for less than $100 (I got mine for $65), they are simple to use and will last forever, and work will work on regular household 110V power. Anything over 1/2 HP and you start getting into higher voltages and multi-phase power.

Anyway, I think If I switched to fire retardant plastic for the tunnel skin and went with either PVC or plywood rings and a wood truss-bridge I could crank one out a backyard vortex for less than $600 that would last for years.


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## Haunted Spider

Your tunnel does look amazing. I worked with a haunt for several years that bought a commercial grade tunnel. We built the bridge ourselves out of steel. We started with a plywood top the first year. Then we noticed everyone looks down to get away from the effect. So we changed the bridge to a stretched steel so the effect never went away. 

At the same time, we had one teenager purposely step off the bridge and onto one of our black light bulbs. He broke it, which was his intent and we had glass spinning now. To remedy this, we put up the no climb fence (2inch by 5 inch rectangles of wire) on the bottom 3 feet below the railing. Now no one could step through or fall through, if they lost their balance. 

A thought in case someone does fall through, the professional motors have a gear slip in them.If you reach out and try stopping the tunnel, it does not continue to spin causing injury to the patron. I don't know if your motor can do that or not, but that is what the professional models have as an added safety feature. 

Good luck with the tunnel. It looks amazing and is well above what I could have done.


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## zombietoxin

Thanks. Yes, the open grating is really cool, but its is also expensive compared to plywood and for reasons you mentioned regarding the broken glass going round n round, we elected to keep it solid to help prevent debris from getting in there. If I had the money I'd probably go with the appropriate polycarbonate sheeting. THAT would be friggin awesome!

Not shown, but mentioned was the 2" black netting we added to the rails to keep debris and body parts on the bridge.

Some of the pro tunnels use a clutch to help reduce injury in the event someone gets off the bridge. We used a belt drive- set to the minimum tension so as to allow slippage if there is an obstruction, but after getting the gumption up and sticking my leg between the bridge and tunnel I can say with experience that a bruise is possible, another injury is less likely. Even with a clutch there is still a potential for injury because the tunnel is moving with momentum, but honestly the risk management and mitigation lies in house management- You have to keep them on the bridge and moving. A video camera monitoring the guests would also be advisable.


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## beelce

DANG !!!!! Love it ZombieToxin


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## adstone79

Great job, what do you do to the inside of these tunnels? I have never been inside one myself, product of such a rural area, I have only been to one haunted house in my life, lucky for me I have a sick vivid imagination, lol!


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## zombietoxin

Hi, not sure what you're asking exactly, but it's a steel frame with a cloth tunnel that is painted with UV paints. Black lights light up the UV paint. 

You should seek out a haunt, they're great! Or better yet- build a front yard haunt and get your neighbors to come to yours!

Happy Halloween!


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## dominic81

ZombieToxin Let me know when you start making these for customers cause I'm blown away at your attention to detail good work!!!!


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## CRAZYBOUTHALLOWEEN

We have also built one similiar to this about 4 years ago, my engineer(husband) would have to give the details but we use some bicycle rims to put the rings on with a motor it works well... but the cloth is a great idea!!! thanks


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## Daphne

WOW! That is freakin awesome!!! VERY well done. Wow.....


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## MacEricG

ZombieToxin: This is a beautiful project. I especially like the painted swirls you did inside the tunnel to work off the black light. You seem to have captured the "vortex" look by making an angled swirling pattern that encompasses the whole length and is evenly spaced around the perimeter with artistic flair - unlike others I've seen that are just random dots, plain circular shapes, or simply splotches of paint.

I also commend you for building a solid project that looks like it will be around for the long haul. Call it my pet peeve, but it makes no sense to me to put so much time, resources and cash into *ANY* project that wont last for years to come. The fact that you engineered it to be quiet only adds to coolness factor. Bravo! 

BTW: I see that you're thinking of adding plexi mirrors at the end to lengthen the tunnel's illusion. Wont that basically reverse the swirling pattern seen in the tunnel and possibly mess up your illusion - appearing something like this:


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## zombietoxin

Hi again- thanks for the kind words! Sorry I haven't contributed much lately, but rest assured I've been plenty busy!

Unfortunately it's all been centered around the framing, plumbing and electrical nonsense it takes just to put on a haunt- nothing spooky there unless you're afraid of crap loads of hard work!

That is until just this week when we passed a major milestone- our codes inspection! Yea for the team! So we decided to celebrate by actually making some prop stuff! Woot more work!

We started our crypt scene! Theres not much to show yet but I will post a teaser pic soon-promise.

It may be slow coming with updates because we work every night- so pardon our lack of posting, please!

Ya know, Mac, I hadn't thought about the mirror image thing... I guess we'll all know some time before October!

-Rob


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## halstaff

Considering your attention to detail on the tunnel, I'm sure your new project will be awesome as well. Looking forward to the pictures.


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## zombietoxin

Ok. Here's the tunnel in its final resting place...


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## zombietoxin

and here's one of the base framing for our crypt area units. Those are the horizontal crypts that will be foam carved to look like dirt and stone. They'll either have buckys or actors laying in them. One has a solid back the other is open on both sides to allow actors to scare through. We'll also have 'other' crypts that you'll have to come and experience first hand!

Back to work now...


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## Daphne

Have freakin' mercy. This stuff looks incredible. I can't wait to see the pictures of the finished crypts! You must have a giant warehouse to store all your props.

You are already hard at it in February, I feel like such a slacker!

Sure wish your place were closer, this would be an awesome field trip!


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## barreto

*Vortex tunnel*

Great and amazing job, I'm starting on a vortex tunnel like yours as I watch your vid. except I'll be using 2-1/2 angle steel with 2X4 tube steel for the cross members every 5 ft.for my 20ft. bridge which will be only about 3 ft. wide in place of the c-channel and 18 in. pieces of 2X4 tube steel for my feet. I have a 1 hp. gear motor I'll be using. 
Just one question where did you get your cloth material from ? anyway fantastic job. here's my email if you can lend any tips my way. Thanks

[email protected]


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## zombietoxin

I found it cheapest at http://www.onlineeei.com/fabrics.cfm , but who knows today- it may be cheaper elsewhere now.

Good luck with your VT!

If I was going to do it all over again, I would SERIOUSLY consider making 2 12' tunnels instead of 1 20'. Because the span is shorter- the bridge frame requirements would be MUCH less and therefore cheaper. Believe it or not a large amount of my expense was in the bridge beams. A 12' span could be done safely with the right lumber, not to mention increasing versatility by way of spinning the tunnels opposite directions when placed end to end, or placing them at a right angle, or even in a u-turn shape.

Man... looking at those pictures of that clean shop area where it was built amazes me... The place is CRAMMED with all manner of haunt fodder now. Can't even see the floor...


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