This is an exercise shown to me by Jason Moran, which in turn he learned from Andrew (Drew) Hill. This is a good warm up, and you can go through playing shells in all the keys in just a minute or so. You can also improvise the right hand, which otherwise follows the Basic 2-5-1 Voicings.
Follow the left hand fingerings exactly as written, this will set up your hand for playing roots with fingers 4,5 and shells with 1,2,3.
Transpose in all keys.
There are little mistakes in transposition after bar 3, up to you to find them!