[0x1ceb00da]

What if there was only one white block on the grid?

[adamschwartz]

The game is initialized with a guaranteed solvable board:

https://github.com/RaymondTana/Lights_Out/blob/31fe5e866c45c...

[bradrn]

I’m pretty sure this case is solvable too. Click the white block, then click all the blocks which turned white after that. This flips each block twice (bringing them back to their original state), except for the original white block which was only flipped once.