[losvedir]

Well good for you for trying an experiment about it.

You might like the book The Design of Everyday Things which is about issues like confusing elevator buttons.

I just flipped through my copy, actually, because I wanted to quote a passage at you, but I couldn't find it so I guess I was wrong: I had thought one principle of good design was a one-to-one mapping of interface features to functionality. Two buttons doing the same thing would break this concept, but maybe it's not a principle after all.