In my project ( http://www.greenfoot.org/scenarios/19126 ) I wanted to create the Tetris-blocks out of 4 small blocks but when they start to fall the one in the bottom right corner of the "square" block waits 2 times before falling so that there is this "Z" shape. Also when I try to move it left and right the formation isn`t as it is suposed to be. But if I change the order in which I create these blocks it differs in the problems that occur. Thank you in advance