The Karplus-Strong algorithm

[NotSure]

Hello,
I assume that the pluck opcode implements the Karplus-Strong algorithm.

I’d like to know which basic opcodes to use to implement the Karplus-Strong algorithm.
In particular for the delay line, maybe with the comb opcode,
but above all how to route part of the output signal backwards?
(see diagram)

Thank’s

[NotSure]

Update,
I found the solution in the csound manual, it’s the example of the delayr/delayw opcode,
in the delayr.csd/delayw.csd files.
delayr.csd