How would you word this: repeated without synchronization?

[MichelRE]

this is a long held chord, end of a piece, and I want each string instrument to be repeating up/down bowing individually, without syncing with the other instruments. The idea is to create a sort of "crowd" sound.

I have to use as few words as possible, obviously, and I'll be translating it into French, so it can't be anything too esoteric vocabulary-wise.

Any suggestions?

[David Ward]

Something like this? I think that's what I've done that has achieved what you are asking for.

You might make that ‘independently ad lib.’ if you feel it's safer, or even ‘individually ad lib.’.

[OCTO]

My idea: (VП freely)