Vase model in the shape of balancing rocks. 

While printing in vase mode with 0.4 nozzle I got some gaps, so I recommend printing with these settings:

• layer height: 0.16mm
• line width: 0.42mm
• walls: 2
• top layers: 0
• infill: 0%

If you have a nozzle bigger that 0.4mm, you should be fine with printing it in vase mode.