Improved Two Part Round Tray

I like the design of the [Dice Tower w/swappable trays](https://www.thingiverse.com/thing:1276711) by [ClericAaron](https://www.thingiverse.com/ClericAaron) but my printer was too small to print either of the original dice trays in a single piece. I wasn't happy with the two-part version of the round dice tray because I would have to glue the two pieces together and I've never had much success with such designs.

So, I designed a replacement for the base part of the original design. In this version, the base extends a bit into the tray and the two lock together like puzzle pieces. This has worked quite well for me. An added advantage is that I was able to style the tongue that connects the two pieces as a small staircase. There's no functional reason for that bit of flair, I just like the way that it looks.

You'll almost certainly need supports to print this design successfully. The tongue is suspended a few mm above the print surface. There might be some clever workarou