Shine

It was a fine line between polished metal and an actual shiny stone, the trolls thought. It was, in many cases, hard to tell what the travelers were passing them, so horrid was their eyesight. And so well-known was the issue, that said travelers often tried to pass off bits of this and that--anything that glinted in the light, really, as proper payment for traversing the troll bridges. At some point, in the grand history of trolling, the collective decided that this was completely, absolutely unacceptable. They needed eyes--someone or something to see for them. But what?