What food represents the three types of rocks?
I suppose a layer cake could represent the 3 rock types. The fillings and frosting could be intrusive and extrusive igneous rock (sills and dikes) each layer formed and colored to show various sedimentary rock, the burnt spots metamorphic rock and the crumb active erosional areas. Cutting and pushing it around could show all the types of local contacts as well as plate tectonics . And you could….. You could become obsessed with this sort of thing.