Modifier
A Modifier adds an effect to a Tile when it is rendered on a TileGrid. There are two kinds:
TileTransformModifier transforms a Tile to another one before rendering
TextureTransformModifier transforms the texture of the Tile before rendering.
Use TextureTransformModifiers, when you want a graphical effect, like glow, flipping, cropping, etc. Use TileTransformModifier when you want tile variations, or more elaborate effects, like FadeIn, FadeOut or Markov.