He was inspired to create this innovative sole pattern after he poured liquid rubber into his wife’s waffle iron.

The resulting waffle-patterned sole provided better traction and grip on various surfaces, making it suitable for running shoes. The waffle sole features a grid-like pattern of square or rectangular indentations, resembling the pattern of a waffle, and it made its debut in 1972 with the release of the iconic Nike Waffle Trainer.