Starting with a simple rectangular box, we are exploring possibilities for "extracting" virtual form with the help of minimal constructs that are, in a way, hidden within its volume. The process is not unlike a (subtractive) mode of sculpting, although the notion of interactivity poses new challenges to an otherwise fundamental concept in visualization. Our current goal is to explore form-making at the basic level in order to provide a comprehensive framework for more complex analyses in the future.