Button, Button? Who's Got the...
Buttons! This exercise was a good way to introduce a physical sensor (button) as a means to control the Arduino. I found the last bit of code in the chapter to be somewhat challenging, with little explanation regarding the new vocabulary that was introduced to help with the "debouncing" issue. Oh well, I sense that things will get easier as we move along :)
Describing a system? Water evaporates from the Pacific Ocean to form rain clouds that are pushed by winds toward land. These rain clouds come against the great wall of the Cascade Mountain Range, and as they increase in elevation they lose their rain. That rain slides back down the slopes to feed the watersheds that eventually fow back into the Pacific Ocean.