Starting with the solid PVC material enables the erosion of the basic form by degrees to get at shapes that are hidden inside. Unlike the lightweight pvc that has the low density core this solid material has the same density throughout. The resulting forms have a continuous shape without edges or contour lines.
This example has an eroded edge working against the circular form to create a slightly asymmetrical shape.
The circular side has a flared interior transition to the edge.
Here the tension between the erosion and the circular can be seen clearly.