Now works with bezier! This is a very powerful expression that you can use to drive all kinds of very cool effects! Based on knowledge from The Power of Expression Book 

Ever struggle to manipulate a simple waveform on a project??? The waveform expression is a fun way to generate a waveform between two paths in After Effects. Created with knowledge from The Power of Expression Book. Just download the After Effects project file to get the expression. Enjoy! :-)

Nice roundup from Boone Loves Video that includes  The Power of Expression book which is a must on any serious After Effects artist's bookshelf!

Learn how to create a Kissing Circles Fractal using Expressions in After Effects using concepts from The Power of Expression Book 

13 Days of Incredible Expressions Challenges. So cool, it's like free plugins! Based on knowledge from The Power of Expression Book