Thanks Garfield,
Yes, the Doepfer A151 quad sequential switch is one of the more affordable switch modules that can be 1 out to 4 inputs or 4 outs to 1 input so bi-directional with a trigger input and trigger reset input as well. It lets you change from 1 to 4 steps and if you leave one of the steps empty can function as a rest between steps in the pattern. Sort of an ancient 1 to 4 step sequencer! I like feeding it with few voices and trigger with Pamela New Workout or a sequencer. Having two or more is even better as you can mix things up a bit. But a matrix mixer does a lot as well so both are perfect with logic modules and random control voltage generators like Wogglebug or Marbles for example.