A system, method, apparatus and product for designing, on a display device, a geometric shape is disclosed. The method comprises the steps of displaying an initial set of similarly structured model exemplars on a display device, selecting a chosen set of models from the initial set of similarly structured model exemplars to apply to a model mix, mixing the set of models consisting of a first portion and a second portion to form a currently displayed shape, providing on the display device at least one selectable feature for manipulating the currently displayed shape, and applying a constraint of the selectable feature to the displayed shape to update both the first portion and the second portion of the currently displayed shape into a new geometric shape design. In a particular implementation, the first portion of the geometric shape is an automobile and the second portion is a standardized human occupant representation.