In this month’s puzzle it was hard to know for sure if you had an optimal solution, but there were a few things to note:

1. There were more laser entrances (24) than exits (21), so not every laser can reach a target.

2. You get more points for a successful laser than you lose for a wall of length 1, so in general building mirrors is worthwhile, even if they’re small.

3. There were some locations where placing one mirror caused 2 lasers on opposite ends to reach their goals.

The best solution we received (and the best we’re aware of) totalled 77 points. It is shone above. Congratulations to Sébastien Geeraert, this month’s high-scorer and winner of a Jane Street t-shirt!