Planetary Dragon Egg.  The linked original file combined a planetary gear easter egg with a dragon scale egg.  Those original planetary eggs were awesome, but took a long time to print.  I resized it to print fast and efficiently.  I like to hand out easter eggs and these are a reasonable size.  

This is 4 inches tall (101mm) and should not require and post processing on the gears.  Model uses just under 100 grams of filament.  I painted support enforces to get best quality. The eggs are positioned to be facing the bambu cooling fan for best overhang performance.  Seam is aligned – if you use a rear seam, it will be visible when the egg is closed.  Arachne walls help avoid odd infill zones.  

If it doesn't spin: 

The seam may need to be broken free.  Slide shim past the seam, between the two halves.  You may hear it click free.  Silk filament eggs would not initially rotate.  Regular and matte pla worked fine for me.  I used a blunt or dull shim to free the seam and allow it to rotate.  This can be a simple thin piece of plastic or cardboard, like the plastic on bambu rfid tags.    

If you dont have a shim, place thumb on bottom center gear, fingers inside the egg and rock it back and forth to free up movement.