Buchla format Eardrill Model 077 Pendulum Ratchet

via this auction

"Pendulum section
The main clock rate goes from about eight and a half seconds per tick up to 10 ms per tick. Pendulum/Ratchet drawing
Transport controls
These do the obvious things to the clock. Sync does one non-obvious thing, though. In addition to syncing the clock, it also resets all the divisors.
Pulse Density Modulation
With the Density control all the way up, the "tock" output is the same as the "tick" output. Turning Density down creates a pulse train that randomly picks pulses from the clock to send out the tock output.

Division A and B.
These are variable Ratchet Divisors that can be freely positioned from a divisor of one to over a hundred. The divisor values can be limited to some interesting number sets, including primes and the fibonacci series. The limit options are arranged in decreasing density:
limit off
odd (1 3 5 7..127)
even (2 4 6 8..128)
primes (2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97 101 103 107 109 113 127)
trip (1 2 3 4 6 8 12 16 24 32 48 64 96 128)
Fibonacci (1 1 2 3 5 8 13 21 34 55 89 144)
^2 (1, 2, 4, 8, 16..128) Ratchet section
can be clocked from an independent source, although it will still listen to the sync jack as noted above. Either the tick jack or the tock jack can reach the Ratchet in jack with a shorting plug. Fixed divisors
Divisors that include common note values (2s column) and triplet values (3s column)."