Analogy draws on similar situations to provide ideas for invention and design. Alexander Graham Bell used the analogy of the human ear when designing telephone apparatus to receive sound. As mentioned above, his first receivers were much better than his transmitters where the analogy with the ear didn't work as well. When devising their flying machine, the Wright brothers used the analogy of soaring birds twisting their wings to restore balance. They designed the wings of their aircraft to be able to warp to achieve the same effect.
The moment of realisation of the answer to a problem, the flash of inventive insight portrayed by the eureka moment, is an important component of the inventive process. Without it there would be no significant improvements to existing technology or its products. But Usher believed that such acts of insight are as important to minor incremental inventions as they are to major radical inventions. And it's worth noting that insight doesn't always occur as a flash; sometimes it's a steady and growing awareness of the solution to a problem.