In art we have to make a 'funky head'....?

Its a polystyrene manikin type of head, the main materials to build on our funky head to make an alien is mod rock and cardboard. the art teacher said we can bring in our own materials, i want to make my head scaly but i don't know how to make this texture, i was thinking putting kind of tear shape raised mosaic pieces all over it and then covering it with a layer of mod rock but cannot find any mosaic piece like this, any idea where i can get them? or any other ideas to create the scaly effect? thank you guyssss, biggest help everr :D