Filament sample holder Stackable/Magnetic

I designed this filament sample holder to be stackable. The holes fit the earth magnets from Harbor Freight so they will stay together when stacked. I also created a lid for a single or top box. https://www.harborfreight.com/10-piece-rare-earth-magnets-67488.html
Yes the holes for the magnets are oval. I somehow got them out of round when I was creating it and didn't notice until after the first print, so in order to keep all my boxes the same I left it lol.