This puzzle was frustrating, and not in a good way. This would work so much better as a 9x18 puzzle without those little "lights", and even then, it would be a symmetrical disaster. Terrible puzzle, and even with Eirin's help, the lamp itself is downright mean.
For those who can't find them either:
*spoiler*
If the columns are counted 1, 2, 3,... and the lines A, B, C,... they're at:
A1, B2, B10, C9, K2, L1, L9 and M10.