The Logic Pro X 10.1 update has some pretty interesting and in-depth additions. The Brush tool being on of the them. But it can do so much more than simply paints notes as patterns in the Piano Roll editor... especially when used in conjunction with Time Handles (also new in Logic Pro 10.1).
David Earl aka. SFLogicNinja, shows some neat tricks in this video below taken from his complete course: Logic Pro 10.1: In Depth at AskVideo.com.
Watch the rest of the videos from the course by either subscribing or downloading the course at AskVideo.com here: