@Orangery Yes, sorry about I hadn't tested it and the numberbox outlet was not connected to the [+ ] object, but worse than that was the random notes cause some notes hang when playing more than one note if playing polyphonically. The best I could come up with to address that, was to count the note-on and note-off and when sum was zero perform an all notes off (cc 123).
out-of-tune-3.pd

@Orangery try adding these

@dreamer I was just checking about the dsp when you posted, and you are right of course Thanks again

@dreamer Solved, updated plugdata to v0.93 and I think I needed dsp on to run the metro. Anyway thanks for great product

@Orangery I'm not that good on music terminology, but here I've added an hradio of 13 cells that when set greater than zero will also play a note that many semitones above the original at the same velocity
out-of-tune-2.pd
I've just noticed today when you first open the plugdata.vst edit button there is a plug icon to enter plugin mode

@dreamer I have followed the instruction on sites you directed me to and compiled the plugin. I loaded it in vsthost but it doesn't output anything
What do you think is missing?

@dreamer please don't take offence, at my age I need all the safety precautions I can get, Anyway I just checked and the whole toolchain business is all intact now so I tried to compile it. the vst has no inlets or outlets or Gui, I guess it doesn't like me

aha! @dreamer now I see why McAfee keeps quarantining heavy.exe, It's trying to protect my sanity. I don't think I'll bother

@Orangery you can open the outoftune.pd that is in the outoftune vst3 folder in plugdata.vst3 or puredata to see the difference
which are the control connections are now wireless using send and receive, there is a second toggle that opens a second spigot allowing the metro to bang the random continuously instead of only when a note is pressed and there is also an offset slider which raises or lowers pitch centre

@Orangery I have just notice that my mathematics is wrong [- 4096] should be [+ 4096]
I also failed to mention a plugin called Camomile by Pierre Guillot that allows for the creation of vst3 from a Pure Data patch. Its not too difficult but It took few goes to get the settings right. All the files in the zip need to kept together in a folder "outoftune" and copied to your vstplugins folder.
https://github.com/pierreguillot/Camomile/wiki

I've used an updated version of out-of-tune.pd to create outoftune.vst3 using Camomile
outoftune.zip