Optical testing - too easy?

Before dark, I tried TXing from one side of the house to the other reflecting my 481THz optical beacon off the windmill. Even by ear in 600 ohm phones the signal was very clear and very easy to find. This was only about 100m path length, but I wanted to check the gear still worked as it is a long time since I used it. Not sure what to try next as I still feel very wobbly on my feet and tire easily. At least I know my homebrew optical gear all works still.