Paper folding technique, please

October 23, 2007 4:45 PM

Is there any way to divide a square piece of paper into absolutely perfect thirds without a ruler?

I feel like I remember learning a method for this in an origami class years ago, but my memory could be completely inaccurate. I've been fooling with this same paper square for ages, and I can't get thirds. Help please, or put me out of my misery and tell me that I need the ruler.

posted by Wroksie to sports, hobbies, & recreation (6 comments total)

I got this by typing "origami thirds" into Google.
posted by vacapinta at 4:52 PM on October 23, 2007 [2 favorites]

Yes:
curl the paper (do not crease) so that one end one edge bumps into the paper itself and the opposite edge goes as far as it can while still overlapping the paper itself. then crease the two folds and you've got thirds.
posted by oneous at 4:53 PM on October 23, 2007

I think oneous is describing the technique I use, which is imperfect because you have to do two concurrent folds, but it usually works for me:
- grab both sides of the paper and bend them in opposite directions so the paper is in an 'S' shape
- slowly squash the S, adjusting as you go, so that the edges are lined up with the bends in the paper as you bring them together
- crease the bends. the result: Z, where all three segments are the same length.
posted by PercussivePaul at 5:23 PM on October 23, 2007

vacapinta's link does show the mathematically correct way to do it, although it's hard not to think that practically speaking the normal letter-fold method others described would work just as well and leave fewer creases in your paper... still neat geometry though.
posted by mdn at 5:54 PM on October 23, 2007

What I do when I'm trying to fold paper to fit into one of those 1/3 size envelopes is:

Fold it in half, but make only a small "pinch" crease at one edge of the paper so you know where half way is.

Fold one side over, and try to line up the mid point of this section with the mark you made in the middle.

Then fold the other side over to the edge to match.

With a little practice you can get it pretty spot on. It's not perfect but it's more accurate than trying to make two folds at once, for me.
posted by jon4009 at 11:39 PM on October 23, 2007

While doing origami I use the iteration method detailed here, and leave a small crease as a mark each time.
posted by algreer at 5:37 AM on October 24, 2007