The process of taking direct products can be repeated to obtain rings like R × S × T, or the n-fold product of a ring with itself: Rn = R × R × ··· × R (n factors).
There is of course the question whether, say R ×S × T,
(R × S) × T and R × (S × T)
all yield the same result. The answer is `yes' in the sense that they
are isomorphic.