Build your own lazy operation evaluator in Elixir

With Elixir, the struct is immutable which means it can be safely accessed in parallel without dealing with locking/mutexes. You also have a horizontally scalable "cluster" of machines (even on a single physical machine, this is over-simplified but it's an accurate mental model) so you could easily have some producer that is creating these expensive math ops and pushing them onto a queue, and then a pool of "workers" that run the actual execution distributed across cluster CPUs. And this can be done fairly easily with idiomiatic Elixir, without adding external dependencies! Really neat stuff.