There is a known issue with puzzle 16 not showing as 'completed' even if it is completed correctly. We'll have it fixed soon...
So, I just have to wait...
But:
There is also a workaround with version 1.00.03. You need to make sure that the disk is in the 'wrong' position until the beam of light is fully lit. Then turn the disk.
as I didn't read it before doing it, I put the disk in the right position (on the furthest left) and the beam of light arrived on it and… every thing happened normally. Well I have the version 1.00.03 but not this _bug_!
