Alberti Cipher Disc (Caesar/Vigenère Cipher Wheel)

A laser cut replica of the [Alberti Cipher Disc](https://en.wikipedia.org/wiki/Alberti_cipher_disk).

The SVG file consists of several layers that can be combined in different ways
depending on the material to be cut.

For acrylic the layers
* engrave disc 1
* engrave disc 2
* cut disc 1
* cut disc 2
* deep engrave disc 1

can be used to get a larger disc with a circular pocket in which the smaller
disc can rotate freely without the need for additional fixation.

For wood the layers
* engrave disc 1
* engrave disc 2
* cut disc 1 (2 times)
* inner cut disc 1
* cut disc 2
* thumb hole

result in a back plate, an outer ring and an inner disc.
The ring get glued to the back plate. The inner disc can then move freely
inside the ring.

For paper and cardboard the layers
* engrave disc 1
* engrave disc 2
* cut disc 1
* cut disc 2
* center hole disc 1
* center hole disc 2

lead to two discs with concentric holes that can be mounted together
with a clip or pi