I invited my friend, Will, to exchange postcards with me for a month. We both went out to the hardware store and collected as many shades of blue paint chips as we could find. Every day, we would take our stash of blue samples outside and try to find the one that best matched the color of the sky for that day. On a postcard, we would record where we were, the date and time, and attach the paint sample. This is the record of all of our sent and received postcards.