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Picture of Catahedron Costume
What's cuter than a platonic solid? A cat dressed up as a platonic solid for Halloween!

This instructable details the making of a soft quilted tetrahedron costume for the more patient of my two cats.
 
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Step 1: Choose fabrics and preprocess them

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The first step in any quilt is to pick out fabrics. You will need at least 4 colors, two for the contrasting triangles, one for the outside border, and one for the backing. I was working with fabric scraps from other quilts, so I used more colors but whatever you've got will work. Be sure to wash, dry, and iron all fabrics at least once before you start working with them. There's nothing worse than finding a finished product ruined in the wash by runny dyes or fabric shrinkage.

You'll also need an attractive color of quilt binding. Binding can be purchased at most fabric stores (I use Joanne's). The binding is a cloth strip that will sandwich the outer hem to create a finished edge. Also make sure you have a color of thread that matches your fabrics.

Step 2: Cut triangles and piece them together

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Using a rolling cutter, measure and cut equilateral triangles from the chosen fabrics (the size will vary depending on the size of your cat). You will need 9 of one color and three of the other. Pin the triangles together one pair at a time, sew, and iron the seams flat immediately. Never skip the pinning or ironing steps! Quilting is all about patience; you will get far far better results if you are methodical.

Measure a strip of your 3rd contrasting fabric for the outside edge; the border shown in the pictures is a 2" strip. When the 4 triangles are sewn together and ironed into a bigger triangle, pin the border on the edge and sew in place. Once one edge is attached, cut the edges flush, iron flat, then repeat for the other edges.

Step 3: Attach batting and backing fabric

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Take the backing fabric and lay it flat on your work surface, right side down. Place a layer of quilt batting over the fabric, taking care to smooth out any wrinkles. I used polyester low loft batting in a "child's blanket" size. Anywhere that sells quilting supplies will have a ton of options for batting lofts (how thick it is) and material (cotton, polyester, etc.). A lower loft is better for this project because it will keep the overall product lighter and be easier for the cat to wear.

Place each pieced top right side up on top of the batting, making a batting sandwich, and pin it into place with basting pins (which are like safety pins, but shaped more conveniently for this purpose). Once the batting is pinned on, cut the sides of both the batting and backing fabric flush with the quilt top. It's easiest to use a rolling cutter and straight edge to do the trimming all at once.

Step 4: Attach binding, quilt along the color borders

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For ease of construction the triangles will all be independently finished and then sewn together later.

Pin the binding strips to sandwich all three edges of each triangle. Fold the edge of the binding under at the corners to hide any unfinished edges. With your sewing machine set to very slow, carefully stitch the binding in place on all 9 edges. As you sew the binding you should aim your stitches at the very edge, no more than a millimeter from where the binding meets the quilt top.

I also chose to quilt another line a quarter inch out from the binding seam. This gave it a nice visual border and took care of holding the binding on at any of the points where I messed up on the initial seam. Specifically, it's easy to have stitches that are accurate on the top, but that miss the binding edge on the underside. The second line of stitches takes care of these cases and reinforces the final product.

While I was at it, I stitched across the seams where the black border met the large triangles, and along the color borders between the inner triangles. This sort of stitching is what gives it that classic quilted look, and also keeps each triangle together flat as it flexes. Try to use one long line for all your quilting stitches; you want as few loose thread ends as possible.

Step 5: Cut head opening, assemble tetrahedron

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Pick one of the finished quilted triangles and cut a smaller upside-down triangle out of it, as an opening for the head. Use a wide sewing machine stitch to finish the cut edges. This was the part of the project I was least happy with the finished look of. If had it to do over again I would have made the head-triangle out of three smaller triangles with finished edges, rather than cutting into it and attempting to finish with sewing machine stitches. However fortunately the border doesn't really ever show while the cat is wearing the costume.

Using a color of thread that matches your binding, sew the edges together. Place triangles back to back (right sides out) and simply stitch along the edge. Though this will create a lip on the outside (showing edge) of the final product, because the triangles are already finished with binding I consider it aesthetically acceptable. Repeat process with the final triangle and the last two edges. After the edges are sewn together you should have a soft pyramid, almost capable of standing on its own.

Step 6: Initial fitting

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At this point I stopped to test how the tetrahedron would look on my cat. My hope had been that the stiffness of the edges would be enough to make the soft tetrahedron stand on its own once it had a cat inside. However as he started walking around it became apparent that a frame was required for it to maintain its shape, especially when you consider how the tail deforms the soft sides. I had thought that the tail could go under the bottom border, but my cat had other ideas.

Step 7: Create wire frame

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After the initial fitting, I decided the costume needed a frame for full effect. Take three wire coat hangers and bend completely straight using either your bare hands or pliers where necessary. Once you have a long length of straight wire, measure it against the tetrahedron edges and bend it into a triangle, duct taping the edges together. Make sure that the beginning of each wire is not at a corner, but is in the middle of an edge. This will make it much more stable and easier to tape safely in place.

Make three wire triangles the size of the tetrahedron sides and duct tape them together into a pyramid. Make absolutely certain that all sharp edges are firmly duct taped in place so that there are no unpleasantly pokey parts to injure your cat. Forming the pyramid out of three finished triangles has the benefit of creating nice smooth pieces, and also having two wires along each edge will give it extra support because coat hanger wire isn't that strong.

When the frame is ready simply pull the cloth over it and use safety pins or basting stitches to hold it in place. You don't want to permanently attach the frame because you may want to wash the costume in the future. All that you need is something to hold the bottom edge of the cover to the bottom edge of the frame, and safety pins hidden on the inside work perfectly for that.

Step 8: Final fitting

Once the frame is attached to the quilt the costume it's ready to go! Gently coax your cat into it and admire your work!

At first I was worried that my cat would be unhappy wearing the costume, but as it turns out he really likes it. Like many cats, he's got a strong instinct to sit inside of things so even when I took the costume off of him he got right back in. I would worry about him injuring himself if he wore it while I wasn't directly supervising him, but he definitely seems to appreciate the concept. Also, he appears to be able to walk around freely while wearing the costume, which is adorable!

While your cat is not wearing the tetrahedron it can be placed on its side to make a quilted cat tent-nook-bed thing, which both my cats (even the one that's far too skittish to be costumed) like very much.

Happy Halloween!
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twilightfox10 months ago

It's the Triforce!!!!

Really great and fun idea you have and very aesthetic to look at. We are cat people too and I have a suggestion for another use. Make it a little bigger, make a bottom triangle, sew it up well, beef up the frame, add a much larger entry and suspend it from the a hook loop just high enough to make an enclosed cat hammock. I bet you could make and sell thousands to pet stores everywhere...no kidding!
lugreen2 years ago
love it and the pun! :)
lugreen lugreen2 years ago
and am now thinking (as my cat does NOT do Halloween) if I could make a dodogahedron??
oshiete44 years ago
The costume would be lighter and safer if the frame were made of plastic drinking straws. We used to make tetrahedron kites out of straws, string, and tissue paper. Pass the kite string through five straws (just suck the string through from the other end), tie into a <|> shape (imagine those triangles being a bit bigger there!), and add another straw for the final leg of the tetrahedron.

With the fabric, though, you probably could dispense with the string, or just use a thin elastic. No worries regarding poking wires!
mrigneous6 years ago
who thowz 4 sided dice... honestly?
Yeah, I think this die is "loaded" it always lands on 4. :D

(I am SO gonna make one for "mellow boy cat"
If you put some numbers on it you'd have a bona fide 4 sided dice. If you've got a bunch of cats you could make a complete set of kitty dice! Lifesize dnd anyone??
Haha. The d20 could just be a 20-sided cat-sized hamster ball. =P
LMFAO
Laura.D4 years ago
I love your cat he's such a cutey
Laura.D4 years ago
That's cool but my cat would scratch my face off if I tried to put that on him
dombeef4 years ago
Im in your quantum catahedron, maybe.
seanturvey4 years ago
You could also make Barkminster Fuller's famous D-O-Gesic dome.

Ausm4 years ago
That's pretty clever.
merijnvw4 years ago
hahahahaha!!!
So cute...I can't believe the cat likes it so much. It's like a mini house for him too. I can't even get my dog to wear a shirt, much less a costume. Nice instructable.
Does the cat "Like It" or is it thinking up new and painful ways to get even at about 3:00 in the morning....LOL
That's adorable!
red-king5 years ago
bad pun. good instructable.
Instead of a catahedron, I might make a pyramid version of this. thanks for the idea!
{tauney}6 years ago
junge6 years ago
SEhr interessant, aber was soll das darstellen oder was für ein zewck hat das Derieck. Sieht echt lustig aus *lol*
What a cute, funny idea. You have a very patient kitty.
zimmemic256 years ago
i like the pics where the cat is sitting inside the costume and carefully looking through the hole :-P
That's my fave image too.
christineU6 years ago
I can't get over the cuteness of your cat. I especially love the overhead shot in step 8, with the head and tail sticking out of the awesome costume. It's so great that the cats actually like it.
maicoh (author)  christineU6 years ago
Awww, thanks! He's an incredibly cute fellow, but but that's how he gets you! He may look sweet, but he's really full of mischief.
I like the last picture where he is in the costume looking out. It's really cute!
Plasmana6 years ago
That looks really good!
SFHandyman6 years ago
Cats, Platonic Solids and Quilting. Who would have thought they go so well together? 5/5 Too many laughs at the great photos. Thanks
P.S. I saw your stash and I'll raise you one.
=SMART=6 years ago
Awwww that is soooooo cool !!! Favrouited + 5*
espboy6 years ago
WTH? LOL!
AznPanda6 years ago
lol ;P
MrRodrigez6 years ago
LOL this is soo adorable! My cat would rip my face off when I would try to fit her in it though...
Funny costume! I love the originality! 5/5
fwjs286 years ago
what about a dodecahedron!!1that be awesome.....
gabbycat6 years ago
that is the cutest thing I have ever seen. But my cats wouldn't talk to me for a week.
im concerned
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