Max for Live *step -- Step Sequencer
*step is a step sequencer midi effect.
While it is possible to edit sequences of notes with individual pitch, velocity and duration in the main level window, another sequence related to a chosen subdivision grid can be individually programmed to run in parallel. Both sequence level windows can be filled randomly.
Furthermore it is possible to assign some deviations within a chosen range as well as every sequence can run with a certain decrease or increase of tempo on its last event to result in some periodic but non-circular cycles.
Further documentation can be found in the Max for Live device if Ableton Live's Help View is turned on.