Schmurple, here is my theory:
There are bugs in the physics engine of this game that cause an effect you may have heard of called the "dark force." This happens when endnodes of like materials overlap but are not connected. The program tries to separate these endnodes and when they are constricted, it creates stress and sometimes movement.
The "Force" explained...
viewtopic.php?f=3&t=237Force Paddles Explained...
viewtopic.php?f=3&t=1459In your level, your anchors are close enough together that the endnodes of the metal bars are overlapping, causing "dark" stresses in the metals. The weight of the dillo moving the plate downward adds to these stresses, causing the bars to act as a spring. They want to move back to their original position faster than they normally would. I like your discovery. Again, this is only my theory and may not be 100%, but probably pretty close.
Incidentally, if you level out your metal sheet, the dillo will stay centered and bounce pretty much indefinitely.
Here's an interesting variation. I only removed 3 metal bars from the right side. This causes the dillo to roll, a phenomenon a little harder for me to grasp. There are obviously more stresses on one endnode of the metal sheet than on the other.
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