As Pam and I were driving home with our newly adopted dog, Oliver, we were listening to Brian Eno’s True Wheel from his Taking Tiger Mountain (by strategy) album.

I happened to be driving pretty quickly at the time. Just as the song was getting to the best part, traffic slowed down and we started inching along.

I said to Pam that True Wheel is one of those songs that are best when you’re driving at r17. I explained that r17 was detailed in the first Hitchhikers Guide to the Galaxy book.

Here is the relevent quote:

R is a velocity measure, defined as a reasonable speed of travel that is consistent with health, mental well-being and not being more than, say, five minutes late. It is therefore clearly an almost infinitely variable figure according to circumstances, since the first two factors vary not only with speed taken as an absolute, but also with awareness of the third factor. Unless handled with tranquility this equation can result in considerable stress, ulcers and even death.

R17 is not a fixed velocity, but it is clearly far too fast.

R17 is one of the best words for quickly describing something very complex.