Check out this article on Smashing Magazine about propaganda art. (Love the M&M ad campaign poster!)
The definition for plasticine is “a synthetic material resembling clay but remaining soft; used as a substitute for clay or wax in modeling (especially in schools)”. There’s something very whimsical about this form of art that brings me back to an innocent childhood. Take a look at some modern day examples of plasticine usage here, courtesy of Smashing Magazine. I especially love it when it’s used in advertising.

I came across this interesting article on Polish poster art. Definitely worth a look. There are a lot of poster samples and the history is also worth a read.