Even out a run with shifting accents
When a fast run in one hand comes out uneven, Shifting accents splits its notes into groups of four or three, marks one note in each group with an accent on the score and plays it to you once. With each take the accent moves to the next note of the group, then you play the run as written. Only the run's hand is listened to; the other hand can play along or rest.
After a take, choose Practice with shifting accents
It's right under the button that polishes those bars in the result; if that button shows another drill, pick it from Other practice next to it. While you're practising a spot, Other practice in the bar at the bottom opens it too.
Listen once, then move the accent with each take
From the run's first note, sixteenths, thirty-seconds and eighths across two beats are grouped in fours, triplets and sextuplets in threes. The accent (>) on the score starts on the first note of each group and moves one note along with each take, up to the fourth in groups of four. After each take you see whether every note was there and the accented note came out loudest in most groups; if not, you play that take once more.
Play the run as written
The score goes back to how it's written, and this take carries on your practice of the spot at the same speed. Start shifting accents again whenever you like, or simply keep repeating.
Moving the accent through a run is a long-standing way teachers use to even out fast passages. As each finger in the group takes its turn at the accent, every finger learns to play strong or light on cue, and finishing as written carries that control into an even run.