One of the most flexible tools in a new producer's arsenal is the Pattern Sequencer. Also known as “Step Sequencing,” Pattern Sequencing lets you create a beat using a grid.
In music production, a sequencer is a hardware or software device designed to record performance data and play it back in sequence, or in a specific order of events. Early sequencers were analog and programmed by setting a series of voltages (representing pitch) with potentiometers that triggered VCO's.