Folding Paper! Such a pretty effect, such hard maths! Drag the edge with the mouse to fold, drag the middle to move. Drag with the mouse (by the edge to fold, middle to move) Press [1,2,3,4] to select paper sizes. Press [Space] to flip the paper over. Press [U] to undo the last fold. Press [Arrow Keys] to zoom in and rotate. Reset the project after around 7 folds otherwise things can get slow!