Supermodel No. 92 Oscillating Crank Mechanism No.1 & No.2

We often need a mechanism that runs forwards and backwards for different lengths, as people who step forward 4 steps, backwards 3 steps then 2 steps forward etc. There are two models and I have called them No. 1 and No. 2. This is the sort of mechanism that I can see Andreas using on one of his designing machines. Both mechanisms are hand operated but can be run with variable speeds.