Ball inside a ball inside a ball.

Print with support where touching build plate, just for the bottom of the outer ball. The rest prints OK without support.

When complete, the balls will be fused so wait until the print cools and then take a thin screwdriver or something similar and reach through the slots so you're touching the smallest ball. Then give the handle of the screwdriver a light smack to knock the small ball free. Repeat for medium ball.