Many solutions to problems can be reapplied to other problems, in sometimes non obvious ways. If you can accurately identify which parts of a problem are [[the same thing]] as solved problems, you can immediately determine the solution. This idea is popular in mathematics and computer science, but can be applied to everything. For example, many times when you hear someone say something very smart in response to a question, they have probably reduced the question to something they have already given a lot of slow, less smart, thought to. This is an application of reduction --- [[formalizations/indie games are startups|indie games are startups]]