The plastic bottle of water is a very clever and imaginative way of making a 'deck prism'.
What's a deck prism?
Even wonder how they lit the areas below decks in the wooden sailing ships when they didn't want to risk a fire??
http://glassian.org/Prism/Deck/Charles_W_Morgan/index.htmlJust because people lived a couple hundred years in the past doesn't mean that they weren't smart.
