“Visiting an exhibition of children’s drawings, Picasso (according to Roland Penrose) said: “When I was their age I could draw like Raphael, but it took me a lifetime to learn to draw like them.””

I saw this quote on a display when I was at the Picasso museum in Malaga last summer

This is what’s being referred to:

https://en.m.wikipedia.org/wiki/50_Cent_Party