The fill construction idea presented in this lesson is another way of applying the 'R L L F' sticking and will involve playing the shape at certain parts of the bar starting on an '+' count. Obviously you are now used to playing this pattern on a downbeat (numbered count) and that is where it sits naturally so these patterns will create some interesting shapes on sounds. This placement works nicely combined with a Flam.
Below I have listed several fills that follow this construction idea. These start simple to get you familiar with the timing and placement of this idea and get more complicated as you work through.