You will need an A4 piece of paper and a long pencil.
Fold your paper down the middle vertically, to make one long strip.
Then fold it down the middle horizontally, to make a smaller square.
Unfold the paper and on the inside bottom segment make a drawing.
Refold the paper and, on the outside, make a second drawing.
The drawings should show two different poses – like a crouch and a jump…
Roll the top drawing up around your pencil, and then flip between the two, like so…