What characteristics of the painting Guernica make it Cubism?
“Guernica” is not a purely cubist work, though it contains some features of Cubism. It was executed years after Picasso’s innovations and explorations in Cubism and frankly — and not surprisingly, given the subject — contains some Expressionist elements as well. The fracturing and fragmentation of the forms, derived from Picasso’s Cubism, are here placed at the service of representing violence and tragedy; they are not simply unpacked, inanimate, three-dimensional forms explored in two dimensions but ways to express horror and inhumanity. There are many sites discussing “Guernica.” I suggest that you simply google the work. On the first site below, scroll down to the bottom and click on all the links.