PROVO — Soon after the block Y appeared a century ago on the mountain above Brigham Young University, freshmen devised a strategy to punish classmates who didn't show up for the arduous labor of weeding the area around the massive white letter.

The laborers created a password — "Ginger's passionate lips" — and when they returned to campus, they punished any freshman who didn't know the phrase.

Punishments for not weeding or painting the Y in the first quarter of the 1900s included dunking offenders in the school fountain and throwing them in the botany pond. The harshest revenge, halted in 1912 after Provo police intervened, included shaving the head of a slacker and painting an iodine Y from the top of his forehead to the tip of his nose.

No password is required today when the public is invited to a sunset hike to the Y to commemorate the 100th anniversary of the landmark.

The hike, dubbed "Sunset on the Y," will begin at 5:30, timed to allow BYU fans and alumni to watch the Cougars play UNLV in the annual Homecoming football game and then join the memorial, one-mile trek.

The BYU Alumni Association will present participants with a pin to commemorate the centenary hike to the largest college symbol in the United States — 380 feet tall and 130 feet wide. In 2003, College Football News named it the seventh-most celebrated inanimate object in college football.

Maintaining the Y no longer falls to students, unless they have a job with the BYU grounds department. The university has taken several steps over the past 30 years to please the U.S. Forest Service, which owns the site where the Y sits.

The biggest was putting an end to the annual bucket brigades, which lasted from 1911 to 1971 and put thousands of students on the mountain to haul lime-based whitewash up to the rocks.

"I think we all got more paint on ourselves than we did on the Y," said Mark Peterson, a 1971 graduate and now head of the Korean section of BYU's Department of Asian and Near Eastern Languages.

Helicopters took over the hauling in 1972, but an application of gunnite in 1978 made the whitewashings unnecessary.

Now a fresh coat of high-quality, expensive paint can last up to a decade.

BYU lights the Y five times each year, for graduations in April and August, for Homecoming, for freshman orientation and for parents' weekend, but the lights go on for other special occasions, like the day Cougar quarterback Ty Detmer won the Heisman Trophy.

The lights are kept in a buried, bulletproof bunker near the Y, and they are powered by a gasoline generator.