Aspects of algorithms and complexity
John Tromp · Centrum Wiskunde & Informatica (CWI), the national research institute for mathematics and computer science in the Netherlands · 1993
The cover illustration is a graphical depiction of the game-theoretical value of all up-to-4-ply positions in the game of connect-4.The largest disc represents the (empty) initial board, and is colored white to indicate a 1st player win.Drawn positions are colored light-green, and lost (to the 1st player) positions green.The seven sub-discs of all but the smallest discs represent positions resulting from a move in one of the seven columns of the board, as follows:On Labyrinth Problems and Flood-Filling.