"The pessimist sees difficulty in every opportunity. The optimist sees the opportunity in every difficulty."
Can you just smell that? It's the smell of brains hard at work. We're at it again, today we're going to help the painter.
Scott the painter is going to paint the floors of 16 rooms. He is in room #1. He can go through any door (see diagram). He cannot return to any room once he has painted it — slow drying paint! In what order should he paint the rooms? Obviously, #16 must be last.