This is a round box which works fine without the lid cap, but I included the cap in case someone wanted to customize it. For example, I have made one with a cad and one with a TARDIS on top. (I will get pics uploaded tomorrow). I haven't included any method to attach the top yet (maybe a screw system or something soon) so you will have to glue it to use it.I created a cylinder in Rhino, filleted the edges a bit, exploded it, cut through the center to separate a lid from a base, separated the main pieces, grouped them, and did a boolean difference to remove the centers. Then I added an open cylinder with filleted edges for the center to hold the lid on.