-  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 
 
  
local transformations
-  local shape morphing 
-  local contour adaptations 
-  local alpha blending (color and texture)
-  local (multi) texture modifications 
 
  
global transformations
-  shape shifting (in x-y plane)
-  contour corrections -- constraints?
-  alpha shifts -- color and texture 
-  (multi) texture modifications 
 
  
interaction aspects
-  separate control panel vs context sensitive touch interaction
-  shape selection -- drag and drop (from fixed set)
-  sequence (shape shift) modification
-  (local) shape modification -- spreading
-  special effects -- global morphing, style modifications, ...
 
  
shape definition
-  contour maps -- extrusion (scale) profile (scale modifications) 
-  polygon mesh --fixed sequence indexedfacesets (coord transforms) 
-  compound shapes -- morphable proto  (morph propagation) 
-  textures -- including multitextures (alpha blending) 
 
  
transformations
-  time-based (linear) interpolators 
-  discrete representation of morph states 
-  scripts -- constraints & preferences 
 
  
interaction
-  shape selection -- touchsensor, (blaxxun) drag & drop 
-  mouse & keyboard  -- standard sensors (and handlers) 
-  direct manipulation -- graphical editors