A very interesting mathematical puzzle also called as ‘Instant Insanity Puzzle’. In this puzzle four cubes and a tray are provided. The faces of the four cubes are differently coloured.The challenge of this puzzle is to stack these cubes in a column or horizontally so that each side (front, back, left, and right) of the stack shows each of the four colors. This puzzle can be solved by trial and error method but the mathematical solution is based on graph theory.