Comment by abeppu

I for one found the 'how is this possible' video near the bottom of the page to be unhelpful:

- surely for `3 x 3 = 9`, there is some concept of primitive operations?

- I get that replacement of patterns in a graph can be done in parallel, but (a) identifying when a rewrite rule should apply and (b) communicating the state of the updated graph to worker threads and (c) organizing worker threads to agree on which does each task all take some effort. When is this more work than the original computation (as in the 3x3 example)?