I posted this over on porches & decks but it looks like this might be a better place...

So I'm working on this paver patio project...

I have the thing all layed out and it's square. I've dug the hole for the gravel, and have a wooden support form/edging built around. I do have it sloping downward from the house to the furthest point. Here's the thing: when I look at it, it looks skewed to me.

If I face it head on, it looks perfectly level from left to right. If I stand at the side and look at it, it looks like the further side is higher up than the side I'm standing at. I've used a mason line from left to right at various points away from the house -- 2 feet, 4 feet, 6 feet, and used a line level, and the line level says it's level. I've also laid a 2x4 on edge from side to side, with a level on top, and it's level. However, my level is only 2 feet long (patio is 16 feet long).

I generally have a very good eye for this stuff, and it's really bugging me..

Is there some sort of optical illusion where looking at a point 20 feet away looks higher than the point you're standing at? Or am I in big trouble here?

Thanks for any tips...