Double Flat

"Andy!", I heard being yelled from behind me. It was my friend Fred, halfway up the hill, whom I went with for a ride around Prospect Park on Tuesday. He had flatted somewhere between 4th and 5th Ave. We got to the top of the hill and proceeded to do what was needed, fixing a flat. I remarked how he carried not one, but two spare tubes with him. The first one mysteriously went flat in seconds. Must have been a dud. Luckily I brought my pump with me. We inspected the tire and yanked out a huge piece of glass from the casing. The second tube did the trick. Made me think twice about carrying an extra tube with me at all times in addition to a patch kit.