FLOWER Coffee Table

To improve stability,  add a few kilos of sand to the bottom of the BASE; then insert the COVER to hide the sand. 
Print based on your own experience or by testing. A 10% fill should be enough.
A small amount of glue may also be advisable.
The grooves have a small offset to compensate for printing errors. If necessary, soften the annoying roughness with sandpaper. The joint is based on a balance between friction and tolerances; although the design also takes this into account, it may be advisable to test the relationship between print speed and extrusion speed. Obviously all the other parameters and the type of filament contribute to the success of the test. To optimize the joint, you can also use the scaling tool in the SLICING phase with centesimal variations.I would be happy to receive your feedback, maybe some photos. I wish you a good job!