#12 More precise strokes

[Nicholas Bishop]

The simplest tool for this would be a Repeat Stroke
button that would simply add a second layer over what
had just been drawn.

A more compicated tool might allow interactive editing
of a bezier curve over the model, which would then be
'dropped' onto the model to modify depth or color in a
very controllable way.

Finally, a way to create disjointed strokes would be
especially useful when using the Layer pattern, as
overlapping strokes could be drawn that would not
actually overlap when deforming the model.