This is a pair of a scrambler (left part) and a descrambler (right part) which can be used to transmit a secret message over a 1 bit channel (the orange wire).
First set the secret keys (left and right groups of 4 bits) equal and then restart the simulation with the rewind button. After this both receiver and transmitter are synchronized and you can start sending a secret message by operating the telegrapher key (the push button). The message is read by the lamp on the receiver side.
Note that the signal in the line changes pseudo-randomly so that it is hard to intercept the message.
Of course, in the real world in order to synchronize receiver with the transmitter one will have to use a more complicated schematic. This is just a demonstration :)
