@matchboxyouth i would take a look at the help file from the clone object, it works well together with poly and with the "all" message you can send something to all instances. but it also works without clone, like in the poly synth example in 7.stuff/synth.

@oid It seems to me that there is a problem with your MIDI setup.
Two ideas that could help to localize the issue, just guessing because I do not know your setup:
If you have not already, I would install the newest PD version so that you do not have any PD bugs that are fixed already, and you need Jack to route ALSA MIDI:
"If the ALSA MIDI drivers are used, then JACK users can use the QJackctl application (available in most Linux distributions) to connect external MIDI devices and other MIDI applications running on the same computer to Pd."
Regarding your patch, if I am right you could theoretically replace your whole expr with a max object?

max.pd

@oid you are right, notein only outputs single values at each outlet, so unpack and $1 should not be needed.

@oid a stack of size three would not cause a stack overflow. here is something about stack overflow: https://forum.pdpatchrepo.info/topic/10805/struct-pointer-object-limitation/13
in short, in pd a stack > 1000 causes a stack oferflow.
i would use unpack, because i would split the list before spigot if i just need the first value afterwards, but it is not necessary.
but i would use a trigger after $1 because the order of operations makes a difference in the result. on topic: the suggestions from @ingox and @whale-av should work as a solution

@oid regarding edit1: without $1 you send a list with three floats into expr, they are used as $f1, $f2, $f3.
i would use an [unpack f f] after [notein].

here i tried something new with ofelia, but i think the same could be done with pd vanilla too. every bpm creates different melody: bitwise_melodygenerator.pd

some years ago i tried to create midi data from [expr] bitshift operations: https://forum.pdpatchrepo.info/topic/10797/algorithmic-compositions-from-one-line-of-code
here is another thread: https://forum.pdpatchrepo.info/topic/6277/bitwise-operators-and-syntheis

i replaced rpole~ with expr~ for counting the samples in the vanilla sample counter: controlsignalsync.pd

@Boran Robert I do not think that is possible, you can only replace variables. you could create expressions with dynamic patching, but i am not sure if that would be worth the work.
but, you can do iteration with expr. for audio signals you need one block delay, like in this patch:
iterateexpr~.pd
and this is an idea for syncing audio and control rate data, it works on the audio block level:
controlsignalsync.pd possibly the audio frequencies sample size needs also to be n*blocksize for working nicely with the synced control data... interestingly i could use the expr~ iteration to make a vanilla sample counter, i would replace rpole~ with that for counting samples, because rpole~ seems to stop counting after something like 4 minutes...
and, for short expressions [expr] is great, but for long, or complicated expressions it can be more handy to use lua scripts with ofelia.

@4zz4 You can just save the html page to your local drive or print it as pdf?