OP1 Finger Sequencer
I reviewed this synth in the last copy of AudioTechnology Magazine and now with new firmware the OP1 offers a finger pattern sequencer mode which allows you to enter your own patterns on each key (by holding shift) and then triggering your patterns from the keys.
Multiple patterns can play back at once and by changing the pattern lengths in real time you can achieve some really interesting results that will certainly excite those who are fans of Steve Reich