Mathematics and Computer Science Department, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105, USA. shoop@macalester.edu|Mathematics and Computer Science Department, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105, USA. shoop@macalester.edu|Mathematics and Computer Science Department, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105, USA. shoop@macalester.edu|Mathematics and Computer Science Department, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105, USA. shoop@macalester.edu|Mathematics and Computer Science Department, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105, USA. shoop@macalester.edu|Mathematics and Computer Science Department, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105, USA. shoop@macalester.edu|Mathematics and Computer Science Department, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105, USA. shoop@macalester.edu|Mathematics and Computer Science Department, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105, USA. shoop@macalester.edu