This is a test animation to illustrate effects of variations of a hollow form inspired by Keith T's article in the Summer 09 issue of the AAW journal. It starts witha 6x6 rectangle with the focal point 1/3rd down from the top of the rectangle. The animation shows the effect of changing the neck and foot widths and uses five control points (top to bottom)
1. the edge of the neck
2. the upper tangent point to the upper curve
3. the transition point between the upper and lower curve (where the two curves meet tangent to each other)
4. the edge of the foot
5. the location of where the bottom curve, which is both tangent to control point 3 (where upper and lower curves meet) and passing THROUGH the edge of the foot meet the Centerline of the form

The Left Side shows the outline of the shape, the right side the control points and construction lines

Now let's see what happens if you move the "Focus Line"

Now, instead of the look changing a little, moving the Focus Line changes the look significantly.