sole/tween.js — pull request #77 by benjamind (2013-06-04 03:36:07+00:00)
Title: Added yoyo feature allowing you to reverse the tween when it reaches the end

Found this quite useful, being able to infinitely ping-pong a tween back and forth without having to setup duplicate reversed tweens.

Just call .yoyo(true) to make the tween reverse when it gets to the end of the loop.