Wow, nice! I like your answer better than mine. I assumed no repeat junctions, so hadn't thought about this solution. My answer was actually: "15. "Corner" is a bit confusing, but here it doesn't matter. Either go from the top right 3 (edge of diagram) to 5, 2, 4, 1 or 5, 1, 4, 2. Or go from top left 2 (place at which two converging lines or surfaces meet) to 5, 1, 4, 3." This was because I too was unsure about what ksolymosi meant with "corner". Luckily, it was accepted.