From The Ringworld Throne:

"...The Hindmost danced. They were dancing as far as the eye could see, beneath a ceiling that was a flat mirror. Tens of thousands of his kind moved in tight patterns that were great mutating curves, heads cocked high and low to keep their orientation. The clicking of their hooves was a part of the music, like a hundred thousand castanets.
Kick short, kick past, veer. One eye for your counterpartner. In this movement and the next, never glance toward the wall that hides the Brides. Never touch. For millions of years the competition dance, and a wide spectrum of other social vectors, had determined who would mate and who would not."