My first instructor (now in college and moving around, I've trained under several) frequently had us do patterns with our eyes closed and/or turned facing different directions. I agree that it's very helpful with muscle memory, I've frequently found that if I can't remember a pattern, I'm more likely to get it if I start with my eyes closed until I get going. (Does anyone have any idea why that would be?)
Recently,I had an instructor (new for the summer) line the class up and have alternating rows turn around, and then angled everyone so our bodies were lined up like this:
.............../ / / / / / (facing here)
(facing here)\ \ \ \ \ \
................/ / / / / /
..................\ \ \ \ \ \
And we all ran the chong ji. It looked pretty awesome except for a couple kids in the back who started facing the wrong way. We didn't do it with eyes closed, but since people on 2/4 sides are going the wrong way, you can't follow them. It really reinforced the pattern rather than landmarks.