This is an example of morphing a shape into multiples of the same shape. The fact is that shapes have certain mathematic and visual characteristics that cause them to behave differently from eachother. That's why things in nature also have commonplace behavior based on appearance. The shape itself dictates how the material behaves, whether it's rock that is breaking from a wall, or a cell that is dividing. The circles and squares in the molecular structure of these things determine how they connect, and how they break.
Homewerks: To get better at this, practice dividing circles and squares into multiple circles and multiple squares. Do a separate exercise involving triangles. Try not to let the triangle evolve into a square or a circle.