Fuzzy Math




Do you tend to avoid anything that involves math? Are you calclueless? Don't you hate how they call it "the calculus" like it's all high falutin and more important than the other math subjects?

The basic problem is, math has a bad rep. Math was like mental gymnastics class, some people excelled at it and the rest of us just got through it with much moaning because we had to.

That's because they never told you about cuddly math.

I had this idea back in college one day when the professor mentioned how most people have an irrational fear of the integral symbol. I thought, wouldn't it be cool if there was a cuddly stuffed integral symbol that you could pass around the classroom and let everybody play with it and maybe get over that weird fear. Here it is at last.


Step 1: Stuff You Need

an old pillow

some soft fabric. I used a cheap blanket I found in the Ikea as-is department. It is called the "Polarvide" which was $2.00.

Sewing machine

Step 2: Print Out a Poster-sized Math Symbol With Your Printer

I used Paint Shop pro to enlarge a screen shot of some of the major math symbols until they were between 18" and 30" high.

Then I used the poster setting on the printer to print them out 2x2 for pi and 4x4 for the integration symbol.

After it's printed out, sketch a half inch margin all around the whole thing, that will give you room to sew it.

Step 3: Join the Seamster's Union

This stuff is old news, there are so many sewing instructables on this site that I won't go into too much detail.

I pinned the pattern to the blanket fabric (folded over twice). Cut it out and sew it.

I sewed the pattern right onto the fabric because it just seemed easier that way. Also, if you switch to a smaller stitch size as your going around tight curves, the machine goes nice and slow and gives you time to manipulate the fabric around the curve.

Remember to leave an opening for stuffing. Try to put the opening near the bottom of the figure instead of on top, that way it's less noticeable.

Note: Don't bother with the crazy darts. Just trim the margin of fabric down close to the seam (1/8" or so) after you've sewn it instead, it turns out better that way when you go to turn it inside out.

Step 4: Turn the Thing Inside Out

Turn the thing inside out.

This is a job for my recently unemployed butter knife. Use the butter knife to poke the more difficult curves and details into their proper shape.

Step 5: Who Wants Stuffing?

Grab handfuls of the pillow stuffing and start jamming them into the far corners of the thing. Use the butter knife to work the stuffing into the details.

Don't try to shove the stuffing in all at once or it will look all lumpy. Just put in a small handful at a time and work each handful into place.

Step 6: Pi Lashes

Once all the stuffing is in there nice and even, lash together the opening with needle and thread.

When you're done sewing it up, make a mental point to put the needle down consciously somewhere out of the way. I seem to always make the mistake of just cutting the thread and then absentmindedly dropping the needle who knows where.

Step 7: To Wire or Not to Wire

Sigma turned out to be a big problem. I didn't make it thick enough, so it was really hard to stuff and then once it was finished it was just to floppy and depressed looking. So at the 11th hour, I retroactively added a repurposed clothes hangar to the inside. However, adding wire to it makes it decidely less cuddly.

Putting the wire in first made it really hard to get the stuffing into the points and corners.

If I was to do Sigma over again, I would take the wire and wind the stuffing all around it so the wire winds up in the middle and not too close to the surface. Then I would stuff the stuffing coated wire in first and then open up more seams and stuff around it.

Step 8: Cuddly Math!

Well, there you have it: Cuddly math: Qt and Q.E.D.

And on that note... I think this video from youtube says it all...



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    35 Discussions


    9 years ago on Introduction

    Nice. They're quite the sexy nerd toy. :)

    Maybe some Velcro or magnets would be nice to stick them together in various ways.

    And they would be awesome as bodies for soft circuitry. Plushy graphing calculator anyone?

    1 reply

    Do you mean the logical concept "fuzzy logic" or a bunch of fluffy stuffed AND, OR, and NOT gates?

    Either way, I'm all for it ;).


    10 years ago on Introduction

    Oh.... My dirty mind was seeing some weird shapes in that pillow. But then i realised they were not there, but only in my head. :rolleyes: Cool calc pillows!

    5 replies

    Reply 10 years ago on Introduction

    Yes, but what does it say / mean? I'm mathematically challenged beyond BODMAS,


    Reply 10 years ago on Introduction

    In the last frame, what appears to be a tall elongated s is the FUNCTION sign (example: place that symbol here f(x) dx means a function whose derivatitve is f).

    You know the Pi symbol I assume, and then the one that appears to be a capital M on it's side means sumation: sum over … from … to … of


    Reply 10 years ago on Introduction

    I was not aware that the elongated s stood for function. I thought it was just a long s to represent the limit of sums as the change in x (or whatever your variable is) approaches 0... can you explain how it's the function sign?


    Reply 10 years ago on Introduction

    indefinite integral or antiderivative or indefinite integral of the antiderivative of or definite integral or integral from … to … of … with respect to calculus. It is sometimes written straight up and down, and sometimes the top leans to the right.


    Reply 9 years ago on Introduction

    Or if you're still non the wiser:
    the sideays M is called sigma and it means you add together the set of things that come after it.
    the long s is an integration sign and it also means adding, but it's for things you can't easily add because they're all stuck together. it's useful for seeing how much room there is under a line or for seeing how far an imaginary truck would go


    9 years ago on Introduction

    Argh.. My irrational fear of the integral kicks in. Btw good job on the props :)


    10 years ago on Introduction

    This is an awesome idea for my science students. Molecular models help with understanding bonding, so not much of a stretch to relating it to Ionic/Molecular, Acid/Base, Equilibrium...... Off to my drawing board!

    1 reply

    10 years ago on Introduction

    You didn't go to U of M in Winnipeg, did you? We also had a calc prof who talked about people's irrational fear of the integral symbol...