Roll or Stack?
What solid shapes can do
Some solid shapes roll, some stack, some do both! Let’s find out why.
These roll
Round parts roll!
These stack
Flat faces stack!
Shapes with round parts roll (sphere, cylinder). Shapes with flat faces stack (cube, cylinder). A cylinder can do both — roll on its side, stack on its ends! A sphere only rolls. This is why balls roll but boxes stack.