"Blinking"

Yesterday (Sep 10th), I saw many cool assignments. My classmates used various ways to present their games. Two of them used water in their games.

In class, I learned:

1) I can use water to make a circuit.

2) Arduino: INPUT/ OUTPUT/ HIGH/ LOW...

I could not wait to try, so I did my first try this morning. "Blinking" Fortunately, I did not burn anything.