Here is a simple but effective triplet exercise set up in a 4-2-1 grid pattern. The concept of the grid came from marching-band drum lines. It is a system of moving accents through patterns in order to create different rhythmic permutations. I am using the bass drum as the accent in this exercise. The method is to play four counts of kick on the first eighth-note, four counts of kick on the second eighth-note, and four counts of kick on the third eighth-note. For the 2 in the 4-2-1 grid, cut each bar in half and play this figure twice. And for the 1 of the grid, play each permutation one time each, and play the entire figure four times.