Single piece print that folds up to become a bouncy ball. Instructions additional materials: -hot glue gun 1 - print. I printed these with my default settings: 0.1mm layer height and .8mm shell thickness, no support or raft. I used PLA for the prints shown here. 2 - carefully remove from build plate. work inward around perimeter. 3 - put a dot of hotglue on each corner, fold up and hold. 4 - continue until you have two hemispheres glued up. 5 - put glue around seam and close up. note: to get just the protrusions a different color, I switched filament at exactly 2.05mm with the use of a software plugin Result