circlesequencer has many (often arbitrary) keyboard commands:
space: restart
1: quantize off
2: quantize 6 steps
3: quantize 9 steps
4: quantize 12 steps
s: switch smoothing (anti-aliasing)
d: draw sequence
f: draw sequence as shape / lines
q: line width 1
w: line width 2
e: line width 3
r: line width 4
j: jsyn volume 0.0
k: jsyn volume 0.4
g: dump sequence
0: switch allow 0 frequency through (otherwise freq stays the same until next non-zero)

Source code: circlesequencer_full

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