I was just thinking about how Arizona Icon converted co-expressions to a pthreads implementation and suddenly realized it might be to make co-expressions ‘the’ way to get a separate thread in Icon.
But this is NOT what a co-expression is meant for! I mean, this just plain is NOT what a co-expression should be thought of as. A co-expression is a way of making an Icon generator portable and able to read messages. And thus also is best to be FAST...