Circles cannot compose under addition or multiplication. You can combine two blocks to form a new block. You can combine two integers to form a new integer. You

Circles cannot compose under addition or multiplication. You can combine two blocks to form a new block. You can combine two integers to form a new integer. You cannot compose two circles to form a new circle. Composition can either be multiplication or addition. In short integers are monoidal under both multiplication and addition, circles are not as you can't physically combine circles to form a new circle without mutating the shape of the circle itself. This means circles are a bad shape compared with blocks to use for addition and multiplication.