To draw a perfect circle using the pen extension on Scratch, we can use some simple code: pen down repeat 360{ rotate 1 degrees move 1 step } pen up This is because there are 360 degrees in one circle or full rotation. It will take a while, but eventually you will get a circle. But that's a little bit boring. Spirals are much more fun. In a spiral, it starts off looking like a circle as the Scratch Cat draws it, but it changes as he goes along because each time he's moving a bit faster. I've called the speed variable "x". This is the run script: pen down set x to 0 forever{ rotate 1 degrees change x by 0.001 move (x) steps } In other words, each frame Scratch will move a bit faster than the last one. It only works because Scratch needs to complete the rotation and a bit faster and faster each frame, so his speed needs to accelerate so he can do it in the same amount of time as the last frame. Eventually, he'll start to overlap because the canvas on Scratch is limited. Interesting, huh? All art and programming by me(CataPhantomMonkey).
