t is a 16-step timeline [0..15]
assign arrays to names name: expr
return a matrix [row1; row2; row3]
bpm: 140 set tempo (overrides slider)
bpm: 120 120 140 140 ... per-step tempo (any length, wraps)
each row becomes a track. non-zero values trigger sound
the track name picks the voice:
kick => kick drum
snare => snare drum
hat => hi-hat
bass sub => bass synth
bell pluck => bell / pluck
pad => soft pad
anything else => sine synth
cell value sets pitch
cmd+return or eval updates the pattern while the beat is running