Othello game
Source: Japan Mathematical Olympiad Finals 1998, Problem 5
August 3, 2007
combinatorics proposedcombinatorics
Problem Statement
On each of points around a circle we place a disk with one white side and one black side. We may perform the following move: select a black disk, and reverse its two neighbors. Find all initial configurations from which some sequence of such moves leads to the position where all disks but one are white.