The Origami Forum

What is a good method for trisecting a right angle, specifically the corner of a square?

Check https://plus.maths.org/content/trisecting-angle-origami

Why did you name your thread 15 degrees? 1/3 of a right angle is 30°.

Yeah, I've seen that before. Unfortunately, it doesn't work on a right angle because since the first black line is the same as the left side, you'd have to fold the upper horizontal crease to the top-left corner while having the bottom-left corner touch the lower horizontal crease, which is impossible.

I called it that because the use of trisecting the corner is to take advantage of 15 degree symmetry, as opposed to 22.5.

abnyc wrote:Yeah, I've seen that before. Unfortunately, it doesn't work on a right angle because since the first black line is the same as the left side, you'd have to fold the upper horizontal crease to the top-left corner while having the bottom-left corner touch the lower horizontal crease, which is impossible.

I called it that because the use of trisecting the corner is to take advantage of 15 degree symmetry, as opposed to 22.5.

It works for any angle. Just in the step that starts with "The next step is a little trickier...", don't fold the left hand side edge and make the crease that is indicated in this step, to end at the intersection of the top horizontal crease and the left edge.

Thanks, I see that now.

Serendipitously, I folded Komatsu's giraffe this weekend, and the first few steps are a excellent easy way to trisect a corner: