What is the difference between a puzzle and a real world problem? A puzzle is devised by someone, generally with the intent of making a pleasant experience for the solver. In contrast, a real world problem is not guaranteed to have a solution, not guaranteed to have a feasible path towards a solution, and is not guaranteed to be pleasant to solve.
Here is a simple math puzzle. Can you design two six-sided dice whose sum follows the same probability distribution as 2D6, but with different numbers (all positive integers) on their faces? Classic, totally possible.
Here’s a simple real world physics problem: Can you estimate Earth’s equatorial bulge from its rotation speed and gravity? I thought I could estimate this using geometrical considerations, but that gives the wrong answer. The correct solution must account for the gravitational field of the bulge itself, which can be calculated by decomposing it into spherical harmonics. Nobody wants to do that.
Puzzles do not always succeed at being enjoyable. Sometimes you waste a lot of time on a puzzle, and then when you look up the solution you think, “I was never going to get that one.” For example, one time I picked up a puzzle box on a friend’s shelf, despite my friend’s insistence that the puzzle was stupid. After messing around a bit, he showed me how to open it: he slammed it hard on the table to shake a magnet loose. I was never going to solve that one, because I happen to have reservations about slamming potentially delicate objects that do not belong to me.


