A serious case of cerebral palsy that (those with the disease) find fellow cerebral palsy victims (or idiots who will easily follow them) and create a "gang", thus making their embarrassing disease look tight as shit or dumb as hell.
Hood Rat #1: YO NIGGA CHEK DIS SHIT OUT! *cerebral palsy kicks in*
Hood Rat #2: HOLY SHIT IT LUKS LIKE THE WORD BLOOD!
Thus, a gang and gang sign is born.
A gesture made with the hands to signify what gang and set youre from. gang signs can get you killed if you do them in the wrong part of town.
some little wanksta came up in herre throwin up the rollin 60s gang sign and we blasted his lil ass.