I didn't notice this until trying Madster's clip disc effect.
Use the arrow keys to move around, note how the effect matches the objects size and shape correctly ONLY when going up/down/left/right, but when going diaganoly it morphs into a square. Surely that's not right?
I know it's not a huge deal or anything, and unlikely to come up in actual real world usage. But I'm curious if it's a bug or just a limitation of DirectX.