A mischievous prank in 1906 by Brigham Young University’s Class of 1907 led to the creation of the giant “Y” on the mountain east of Provo. After the pranksters formed the date “1907” on the slope and angered the seniors in the Class of 1906, a school newspaper editorial proposed placing a giant “BYU” high on the mountain to advertise the university. The Class of 1906 embraced the idea, and a student committee concluded that three letters were too ambitious and that a single “Y” made of slaked lime on the highest possible site would be enough. Professor Ernest D. Partridge designed the plain “Y” and supervised its survey, with the letter elongated so it would look normal from campus, while three students staked its outline on the mountainside. On May 15, 1906, despite threatening weather, the male student body cut scrub oak, cleared the surface, built a rock frame, and passed lime in a bucket brigade until the letter was covered about one inch deep. By about 5:00 p.m., the work was finished and a giant white letter shone on the mountainside. About 200 female students then arrived with a picnic, and the student body celebrated by parading through the streets of Provo. In later years, students whitewashed the “Y” each spring, added rocks and concrete to its interior, built serifs at its base and tops to create a Block Y, and eventually encased the symbol in solid concrete, with electric lights later used on special occasions instead of open flames.