How did African masks influence Cubism?

i know that african masks influenced cubism but i have no insight on how?How did African masks influence Cubism?
African masks, especially those from the Congo, resemble distorted human faces. Masks like these influenced one of the earliest Cubist paintings, Les Demoiselles d'Avignon, by Pablo Picasso. Picasso and cubist artists who followed him built upon this early cubist work.





Compare these two African masks with the figures on the far right in Les Demoiselles d'Avignon.





http://www.arts.auckland.ac.nz/ahist/art鈥?/a>





http://gc2000.rutgers.edu/GC2000/MODULES鈥?/a>





http://www.moma.org/collection/conservat鈥?/a>