carving

Hey, just wondering if anyone has tried anything like this or has pics of this kind of stuff... maybe like an aztec carving with a mexican/southern amercan locality theme... I always wanted to do a sort of dig site with artifacts, crates, and maybe like an ammo box or jeep car part all...

I'm starting out on a new paludarium project and am planning to incorporate a lot of artificial roots and branches. I'm attempting to carve the basic structure out of sytrofoam (the blue stuff) and am finding that my little paring knife really isn't cutting it (excuse the pun). What do you guys...