I've made this pencil case for my wife, she wanted a case for her pencils so I've made this one as a test for fittings so later i can go for a bigger 48 pencil one, but that's future me problem... I printed it in PETG and it works well on that. 3 or 4 walls and 10 to 20% infill should do, there's a small part that may need support on the Side B, but other than that just print them on their back and everything should be fine

there are 2 versions for this box, with or without magnets, i've just printed one (with magnets) and glue the 6x2mm disk neodimium magnets on the holes with super glue, but you could use the no magnets version, i'm just not sure if the fittings will be good enough for retain the Top part closed with the Side B of the case. The magnet one is snappy and should be good to use, but maybe a little ugly and with exposed magnets because of small clearances for it on the Sides/Top walls...

assembly: this is pretty simple, print the parts and cut some spare filament on the holes as pins for the connections , i used black PETG for the pins and heat the ends to form heads on either end, that works pretty fine and had no issues with it

if You want to remix it or give any suggestions, just go ahead! the project is made on Onshape: here