MathDB

Ali has

6

types of

2\times2

squares with cells colored in white or black, and has presented them to Mohammad as forbidden tiles.

a)

Prove that Mohammad can color the cells of the infinite table (from each

4

sides.) in black or white such that there's no forbidden tiles in the table.

b)

Prove that Ali can present

7

forbidden tiles such that Mohammad cannot achieve his goal.

Problem Statement