MathDB

An equilateral triangle with side

n

is built with

n^{2}

plates - equilateral triangles with side

1

. Each plate has one side black, and the other side white. We name the move the following operation: we choose a plate

P

, which has common sides with at least two plates, whose visible side is the same color as the visible side of

P

. Then, we turn over plate

P

. For any

n\geq 2

decide whether there exists an innitial configuration of plates permitting for an infinite sequence of moves.

Problem Statement