PORTLAND, Ore. — One Portland school is telling some students: shave your eyebrows or go home.

Several students at Centennial High School have picked up on a trend to shave lines into their eyebrows. They say it's a fashion statement; school administrators, however, contend it's a gang sign.

Gresham police say members of Southside 13, a prominent Latino gang in east Multnomah County, are marking themselves by shaving one line into an eyebrow and three lines in the other to symbolize 13.

http://www.foxnews.com/story/0,2933,353045,00.html

1 and 3 makes thirteen. That's beaner math right there.