I'm really glad you mentioned the concurrency problem from day 18, because this was one of those personal "eureka!" moments I had while learning D. I had no ide

I'm really glad you mentioned the concurrency problem from day 18, because this was one of those personal "eureka!" moments I had while learning D. I had no idea that concurrency could be so simple, and this is not even having any special built-in support aside from thread-local data by default. This is all in _user_ code. By that same token, std.parallelism.parallel was one of those things where I just looked at it and thought "man, you can actually _do_ something like that?"