And you had better have a convincing explanation of why your technology would be hard to duplicate. Otherwise as soon as some big company becomes awa… - Paul Graham

You might find contradictory taboos. In one culture it might seem shocking to think x, while in another it was shocking not to. But I think usually the shock is on one side. In one culture x is ok, and in another it’s considered shocking. My hypothesis is that the side that’s shocked is most likely to be the mistaken one.

Some of the patterns in the numbers are intrinsic (e.g. the alternation of even and odd) and others are artifacts of our use of base 10 (e.g. multiplying by 10 is trivial), but both enable shortcuts in calculation.

As for building something users love, here are some general tips. Start by making something clean and simple that you would want to use yourself. Get a version 1.0 out fast, then continue to improve the software, listening closely to users as you do. The customer is always right, but different customers are right about different things; the least sophisticated users show you what you need to simplify and clarify, and the most sophisticated tell you what features you need to add.