From lines to cubes and beyond, the powers of (a + b) expand as
(a + b)¹ = a + b, (a + b)² = a² + 2ab + b²,
(a + b)³ = a³ + 3a²b + 3ab² + b³, and
(a + b)⁴ = a⁴ + 4a³b + 6a²b² + 4ab³ + b⁴,
with each term built from red a-blocks and blue b-blocks in matching quantities. Financial analysts expand (1 + r)ⁿ this way to project investment growth over n years under compound interest.