exercise 1C from Nicolaides The Natural Way To Draw (for some reason... it never says to do 1B but 1B is the same according to the included schedule)
Nicolaides' "gesture" exercise differs from Proko's "gesture" instruction. Proko's is about simplification of the rhythms through things via mainly C, S and I curves which leads to a clean result while Nicolaides' is about scribbling down the figure almost without ever lifting the pencil from the paper. Since I have not yet read the book in full, I don't know whether Nicolaides will move on to something similar later. It's a bit strange to see the same term "gesture" used for different ways of looking at a thing, especially since Proko recommends Nicolaides' book in some video.