Question 12
There are four squares labelled as $I$, $M$, $S$ and $O$, as shown in the diagram. Each vertex of these squares is painted in one of the three colours: blue, red, yellow. A colouring is called “even” if in each of the four squares, the 4 vertices are painted in exactly two colours so that 2 vertices are of the same colour and the remaining 2 vertices are of the other colour. How many different even colourings are there?
