metamorphose parameters
- symmetry -- upper and lower along x axis
- variation -- shifts along x axis, local symmetry along y axis
- shape vs.contour --
- shape -- emergent form
- contour -- intersecting lines (laws of their own)
- form vs. texture --
- form --line drawings, iconic 'Escher' shapes
- texture -- realism, i.e. visual effects and 'Escher' flavor