''In theory,'' the random number generators are in no way threadsafe,
neither the old `rand()`, nor the mersenne twister of the C++ standard.
However, since all we want is some arbitrarily diffused numbers,
chances are that this issue can be safely ignored; because a random
number computation broken by concurrency will most likely generate --
well, a garbled number or "randomly" corrupted internal state.
Validating this reasoning by an empiric investigation seems advisable though.
