Comment 6 for bug 821553

I advise to take Attributes for "artifistic Impassable" (and any other Attributes) but I won't call it impassable Water but DeepWater resp unwadable as if you can swim I don't see a Reason to wall Swimmers (eg Ducks ;).
Attributes for Passing_Matters throw Logic on a Problem which is arithmetic (geometric). Both Ant and Ship can't pass if they can't deal with a Deep of WaterTerrain while a Horse can wade through. We can beat the Problem dead with Logic (Pass-Flags) but we deal here with an geometric Matter and should prefer Aritmethic. For GameMatters like Campaign ("you still can't walk this way..", blocking Fog, etc) we may prefer the Flags but for physical Matters (in particular Geometry - Metry of Geo) we may prefer Numbers. Bread or Butter, what we will take?