Witech (Ola Wistedt and Alexander Andersson) has announced that a first release of BassMatrix is now available as a 64-bit VST3 and 64-bit standalone plugin/application for Windows.
BassMatrix is a synth that tries to sound like the classic TB-303 bassline synth and provides a simple interface to program the patterns. You can use MIDI PLAY to play any note and you can use KEY SYNC to get an arpeggio like synthesizer. Normally you want to use HOST SYNC to sync with your DAW and change the patterns with MIDI notes. There is also INT. SYNC that is useful when you play the synth standalone (there is a loop size knob for this purpose so you can automatically change patterns in live mode).