The Tower cipher is mechanical 3D printable cipher device for education and hobby purposes only. It's based on the similar principle as most rotor cipers. The Tower cipher uses 5mm metalic (or glass) ball as a signal carrier to trace letters through pseudo-random pathways inside rotors.

All details about printing and usage including source models are on my GitHub: https://github.com/assemblerbot/tower-cipher

Usage: 

Requirements:

• around 1kg of filament
• 1 metallic or glass 5mm ball

Printing: Creality Ender 3, Gembird PLA, 0.35mm layer, 0.6 nozzle diameter, NO rafts and NO supports.

I've wrote detailed printing instructions including optimization tips for Prusa Slicer on the GitHub page above - folder STL.

Customization is also possible, instructions and rotor internal structure generator is on the GitHub page, folder Tools/PathwaysGenerator.

Painting is optional but I recommend it for better readability.

Have fun!