I printed it in this in PLA from Cura on my Printrbot Metal Plus.
Cura crashed and lost my settings, so I'm trying my best to remember, but I think I used a .15mm layer height 15% (could have been 25%) infill, 3 top and bottom layers,
I used a box cutter inserted it into one of the slits and gradually turned the part pushing the part into the blade, not the blade into the part. I cam apart easier than I thought, but it still takes some time. I probably took me 5-10 mins to split mine apart.
Otherwise, it looks great. I'll be bringing this to the STEAM Maker Fest in San Diego this summer. I think kids it'll get a kick out of it.