Shift-click for best results (it takes a second to make the clones needed) A hack that makes Scratch faster? Faster than turbo mode? Yes it is! The variable at the top is the items per second that are being added to the list.
This project utilizes clones to add things to a list. The scratch cat creates 300 clones of itself, and then the clones each add items to the list as fast as possible. Without the clones, and on turbo mode, the cat alone can only achieve around 2000 items per second.