In the flat net, square M touches only P and R. Which two letters will ALSO share an edge with M once the net is folded into a cube?

Squares two steps apart along the staircase are opposite: K–R, M–W and P–T. M touches every face except itself and its opposite W, so its four neighbours are K, P, R and T. P and R already touch it in the net, so the new neighbours are K and T.