This is a simple origami frog that jumps when you press on it. I was taught to make it by my parents when I was really young, so it holds a very dear place in my heart.
There are other versions on the internet, but I think this one jumps better. It is actually simpler than the ones on the internet (it doesn't have front legs). I'm not sure if someone just forgot about them when passing the instructions, or if it was a purposeful change in order to make it jump better.
I recently showed my niece how to make it, and she was delighted. I decided to find and send her the instructions, but I couldn't find the exact ones. So I decided to create my own version.
Anyhow, here are the instructions.
How it works #
The spring works because the paper is folded many times, and it gets quite thick through the middle. When we fold it into a Z shape, the thickness of the paper creates tension, and when you press and release the spring, it sends the frog flying.
The smaller the frog, the greater the relative thickness of the paper, increasing the tension of the spring. This means that smaller frogs will jump much more compared to their size, while the really large ones won't jump at all.
Legs variation #
One note: for aesthetic reasons, I usually fold the legs over the center line of symmetry. In my eyes, it looks a bit more elegant. But with the reduced space between the legs, it might happen that you press on it while releasing, preventing the frog from jumping.
Hope you'll enjoy making it as much as I did growing up.