Nested spheres

Just for fun - no known practical, educational, or artistic merit.

I've printed it successfully two ways:

• 0.6 mm nozzle, 0.2 mm layer height. For this it needed supports to keep the tops of the side holes from sagging and/or curling. Use a support angle of 37° to avoid generating unnecessary supports for the inner edge of the top hole.
• 0.4 mm nozzle, 0.15 mm layer height. For this print I didn't need supports.

In both cases I used a matte PLA at a reduced temperature of 195 °C to reduce curling (and to avoid stringing, in the case of wood filament). Suggest printing with all perimeters.