A pane of glass falls, hits the floor, and breaks. Whether it stops at cracks or bursts apart is decided at the moment it lands: the drop height gives the impact energy, and the glass gives the strength it is compared against. Raise the height or lower the strength and the same pane shatters instead of holding together. The drop panel shows both numbers and what they add up to before you drop it.
The cracks are drawn before the fall. The pane is cut along a spider web of radial cracks and rings, and the impact only decides how far and how fast that web opens. So the number of radial cracks, the number of rings, and the jitter shape the pieces themselves, while the burst force and the bounce decide how they scatter and settle on the floor.
Click the scene to drop another pane. Panels move when you drag them by the heading, resize from any edge or corner, and stick to the edges of the screen. Double-click a heading to switch to the fixed layout, where one panel sits in the top right. Click Rollpie at the top left to see the other applications.