Problem of the Week 1230
Imagine that one person is standing at each of the 19881 points on a regular
Suppose a wave of water flows across this grid in linear fashion, starting at some point far away and traveling linearly at a certain slope:
Assume the slope is irrational. Then the wave will wash over the people, one at a time. Therefore, for each starting state, there is an ordering of the people based on the order in which they get wet.
How many different orderings arise in this way?
Source: Problem 339, Math Horizons, Nov. 2016. page 31