Here is a snip from my Practice of "Spinning Song" by Mendelssohn. A real finger-twister! (And it's my own fault - I arranged it.) I suggest a way to get "free" practice time when you are working on a piece that needs lots of woodshedding. (Then you can hear a full performance of Spinning Song from my recital tour of Japan in 1991.)

https://www.youtube.com/watch?v=babB6P3zW08