The array can be shown as 5 groups of 3 showing that 5 x 3 = 15. Or it could be shown as 3 groups of 5 showing that 3 x 5 = 15. This demonstrates that multiplication is commutative. Image caption, ...

Using embedded-array programmable logic, it's possible to build multipliers that run faster than previous programmable-logic implementations. With the method shown here, you can make 4×4 multipliers ...