The exclamation attributed to Archimedes, who is said to have cried out "Eureka! eureka!" (I have found it! I have found it!), upon suddenly discovering a method of finding out how much the gold of King Hiero's crown had been alloyed. Hence, an expression of triumph concerning a discovery.
Work grows out of other work, and there are very few eureka moments. Anish Kapoor
People think of these eureka moments and my feeling is that they tend to be little things, a little realisation and then a little realisation built on that. Roger Penrose