Making something variable is easy. Controlling duration of constancy is the trick.
Think of all the psychic energy expended in seeking a fundamental distinction between “algorithm” and “program”.
If we believe in data structures, we must believe in independent (hence simultaneous) processing. For why else would we collect items within a structure? Why do we tolerate languages that give us the one without the other?
In a 5 year period we get one superb programming language. Only we can’t control when the 5 year period will be.
Over the centuries the Indians developed sign language for communicating phenomena of interest. Programmers from different tribes (FORTRAN, LISP, ALGOL, SNOBOL, etc.) could use one that doesn’t require them to carry a blackboard on their ponies.