- inspect mulmul without intermediate product: to be better only stack must employed (no Vec writes) => addition method split
- make pow log effecient
- consider num ctors for other numbers
- consider shortcuts: 0 * anything = 0, 1 * anything = anything, 0 ± anything = anything, anything / 1 = anything
- array of usizes: reduces memory footprint by double (1001=9, 10011001 = 9,9)