The solution is easier shown than told, so please, see the video. On the off chance the video has become inaccessible, this is the achievement for completing the gravity puzzle at the end of Sector 6. It involves four boxes - two large one and two small ones - that player moves around by magnets. The idea is to gather the boxes in such a manner that for each red column there is a large box and a small box, with the large box resting against the wall and a red column, and the small boxes resting against a large box and a red column.
After the boxes have been aligned in such a way, activate the magnet on the opposite side to the boxed and red columns, and de-activate them as soon as the smaller boxes hit the light beams. The slide faster, so the larger boxes should be on spot with the other light beams.https://1drv.ms/v/s!AkfQ8S6tX3yikg8dGmey8aw-Wiip
(The same solution is presented in the solution for this achievement
and this video,
I just recorded my own gameplay where I solve it a bit faster, but with the exact same method.)