I was studying 12/8 feel in jazz songs, based on John Riley’s Art of Bob Drumming book. Playing that rhythm, you end up playing a lot of quarter note triplets with your right hand. This led me to other rhythmic subdivisions based on subdividing from the quarter note triplet.
The image on the right is about 18th notes as opposed to 16th notes or 24th notes. 24th notes are the equivalent of sextuplets. 18th notes are based on playing triplets based on the quarter note subdivision. There are 6 quarter-note triplets in a 4/4 measure, playing a triplet between each one makes for 18 notes in a measure.
The image on the left is another applied concept on using diddles to induce odd time. This parchment shows two ideas, or the evolution of one idea. The second phrase has a triplet inside the 16th note phrase, starting on the up beat. By applying chops you acquire from working on 18th notes and diddle substitution to create triplets out of even time, you should be able to master this simple trick and use it in your performances. It’s simple but it will make you seem advanced.