This takes place on Chapter Three
. Proceed until you drain the water using the red buttons, and drop down and go behind the stairs to find a 4x3 grid puzzle. The explanation of the puzzle is a little confusing, so bear with me, but the rules are as follows:
- Cells in your line of sight are active
- Moving forward fills active cells
- Cells will only be filled if ALL active cells have room to grow
The same rules apply to shrinking cells as well, except you move backwards. The video above shows the most straight foward solution to this puzzle, using only 4 steps.
After completing the grid, the door behind you will open. Walk through the hallway onto the balcony. Now, you can make the small black planet follow your cursor around the screen, and you'll want to block the sun. Once you do that, a pillar will arise, and the achievement will unlock.