Kids love to play with these cubes but if they're on the floor for a cruiser or walking baby then they get ignored since they're too low. This is a easy way to get them up a bit higher.
Find screws that are long enough but don't protrude through the bottom of the Lack IKEA table. Take into account the depth of the cube too.
Measure where the center of the table is as well as the center of the cube. Match the lines up on all four sides and you've centered up the mounting position.
I simply tied the cube into the table at all four corners. This seemed to be enough to do the trick.
Done. Now most of the puzzles are at eye level and within reach.
Final step. Happy kid. I do recommend baby proofing the corners with some padding. It's up to you.