Measure your circadian rhythms. Use the shadow from the pin to ascertain what your body is doing at that time of day.
The circadian yardstick works by measuring the length of a shadow, which indicates what our bodies are doing according to our circadian rhythms at various times of the day - from peak alertness to an enhanced sense of smell. By intellectually connecting our internal cycles to those of the Sun, the yardstick encourages the user to live in harmony with both. The yardstick is designed for use in Oslo, Norway, with summer readings on one side, and winter on the other.