Parker's raw material. His materials-driven process has evolved over the years. “[At one point] I was building differently dyed or pigmented layers of cement scraps and other ‘inclusions’ onto bottles or cans, and then sanding and cutting them down and polishing the layers. I then moved on to using the same process on a styrofoam form that is later dissolved. The difference is that in the earlier vases there is a bottle or can embedded within the cement, whereas later it's just made of cement, usually sealed inside with wax.”