Signal Arts MAPS sequencer Mid-2000s

The rare, more playable predecessor to the TetraMAPS, the MAPS has 16 banks of 8 sequences, able to run multiple concurrent sequences, chaining sequences to other sequences, modulating sequences by each other, and sending the sequencer output to any of three cv+gate pairs as well as up to 32 channels of MIDI.

Sequences can run at different speeds from each other, sync'd to external trigger, external clock, each with different step lengths.

While you could use it for some drum applications, where this really shines is leads and melody (or bass and acid, for that matter). Unlike most sequencers, you can trigger the same sequence to play from different start points simultaneously, leading to polyrythms that are more difficult to achieve with most other gear. You can also start and stop those layered sequences very smoothly live.