This appears to be the sketch in question, and yes, deciphering it would appear to be a real challenge! https://www.henle.de/blog/en/2012/01/23/%e2%80%9cla-der

This appears to be the sketch in question, and yes, deciphering it would appear to be a real challenge! https://www.henle.de/blog/en/2012/01/23/%e2%80%9cla-derniere-pensee-musicale-de-chopin%e2%80%9d-%e2%80%93-a-sham/ https://www.henle.de/blog/en/2012/01/23/%e2%80%9cla-derniere... ETA (& edited again to fix): If you read it while listening to the YT video in the sibling comment, you can follow along: the A section is the first two double-staves (and you can see the alternate endings and the "3ci" (trzeci) in the middle-right of the page). The B section, on the bottom-right quarter of the page, starts for the first time at 0:40 in the YT recording and goes to 1:08 or so. The C section, which is mostly crammed into the left half of the bottom two double-staves but also some stuff in the middle-left of the page, runs about 1:48 to 2:43.