OK, I must be a dumbs*?t as I am having a hard time with several screens. Like the one with the two see-saws. It seems like I am missing something. I know the principle behind this is try anything, but the things I am trying just don't seem to work right.

For example, (in general, not that it solves any specific problem) how to you make a see-saw like mechanism. I put a triangle to the left of the red object and then draw a straight line such that the middle of the line rests on the triangle. Now I want to draw a box to drop on the side of the line that is up in the air, such that when the box hits it that the other side goes up. Is this not possible?