OSH Park engineer Dan Sheadel created this LED crown entirely from PCBs:

PCB Crown::Project Info

Experimental 3D circuit board, with possible applications as headwear and firestarter

The design files and source code are hosted on GitHub:

tekdemo/PCB-Crown

Dan shares lessons learned from his first venture into designing 3D circuits:

PCB Crown::Lessons Learned

• Avoid having structural components carry signals
• Castellations work, but mind the placement.
• If at all possible, make each component easily testable and self contained
• Don’t try to dual-purpose a component lead as a signal wire.
• Watch your line termination
• Put all connected parts on the same design
• Hobby Iron vs Soldering Iron: Not the same.
• Make a jig, or at least a good assembly guide