Normally, we would expect that each instance of p5 would have its own random seed.
In such case, we could instantiate a newp5 and call its noCanvas(), just for the sake of using its random() method w/ a specific randomSeed().
However, the code responsible to generate seeded pseudo-random values in p5js is a singleton object stored in a closure variable named lcg:
B/c lcg is a closure variable, no matter how many times we instantiate the class p5, there’ll only be 1 unique lcg object shared across all p5 instances!
Instead, lcg needs to be changed into a class property, so each instance of that class would have its own lcg, rather than a shared 1.
BtW, the p5js library is littered w/ such closure local variables, which are a dumb, poor, short-sighted attempt to make private, unaccessible states.
And considering the library is supposed to have multiple instances of it at the same time, it shouldn’t have any shared states at all!
Now, as a workaround, you can simply rewrite the “random.js” file as a class, whose instances will have their own seed state.
