These are simple trays for board game tokens or other small parts.  They have a slight curves to keep tiny bits from getting caught in corners but shouldn't tip over unless you're extremely clumsy.  I made the doubles first to make sure they could stack and since they're hexes they can be arranged in a lot of different patterns.  The other patterns will still all stack together.  I printed all of my trays with PETG so they have a little more flex and strength but PLA should work fine, just know that the walls are pretty narrow. I'd recommend low layer heights for the first few layers to make the curved overhangs on the underside a little easier to print.