Another great Reason Tips video featuring Mattias Häggström Gerdt, dig the "alter notes" idea he uses with Rex files:
"Drums. They're absolutely everywhere and vital to most music. A good drum track can make or break a track. Luckily Mattias has some useful tricks up his sleeve to help you spice up your drum patterns!
Learn about ghost notes, tips for using REX loops to add some groove and how to create complex patterns in simple ways using polymeter."