Enclosure joint for foam board enclosure

I whipped this up in fusion 360 for an enclosure to hold my printer. As I am 13, I didn't have much to play around with so I went to Walmart and bought some foam boards because I figured if foam is used for insulation, wouldn't it be good enclosure material?(plus they were only like 3 bucks each) This joint will tightly hold foam boards together so they meet in a corner. I printed 8 of them (one for each corner of the enclosure) and then simply cut a foam board to fit on top. Very cheap solution