Non-photorealistic techniques are used in Computer Graphics to render scenes
that have an abstract or painterly feel to them. However, most such techniques
usually employ a source image as input in order to produce a stylized image as
output and they use stochastic methods to distribute strokes or other primitives.
This makes it dicult to extend such methods to video and animation, as sim-
ply applying the technique to each frame results in a noisy looking sequence,
commonly known as the shower-door eect.