I'm not a native speaker, but still have a pet peeve for that one. It's "line-of-sight" (http://en.wikipedia.org/wiki/Line-of-sight http://en.wikipedia.org/wiki

I'm not a native speaker, but still have a pet peeve for that one. It's "line-of-sight" (http://en.wikipedia.org/wiki/Line-of-sight http://en.wikipedia.org/wiki/Line-of-sight). Light travels in a straight line over (human-scale) long distances, so you need a straight line free from obstruction to see between two points. I'm sure you know this and just made a typo, of course. Thanks for the additional information about this interesting solution.