The term 'I've Found It!' is often used to express joy and excitement when something has been discovered. This phrase can be represented in two different ways in a crossword puzzle: Eureka (6 letters) and AHA (3 letters). Eureka is an exclamation of joy or triumph that is attributed to the ancient Greek mathematician and philosopher Archimedes, who is said to have shouted it when he discovered a method for determining the purity of gold. AHA is an expression of understanding or realization, often used to indicate that a solution to a problem has been found.