. >> steve castillo is also serving time in the shu, convicted in 1987 for first-degree murder, his sentenceto life. >> escort coming in. >> i think probably the main thing is staying busy, trying to find something positive to do. people start getting that rage. before you know it, they start disrespecting each other and it gets ugly. i've seen a guy sitting down playing chess all by himself with chess pieces made out of his own feces. guys walking back and forth just pacing the cell, buck naked. get these little small plastic state cups, issued cups and they will sit and they will just bang on that on the sink hours on end, all day, all night. just totally lost their mind, you know? >> some of us are stronger than others and i think that's what pelican bay is about. only the strongest are the ones that are going to make it, you know? so, this is it right here. everybody here is pelican bay but when it comes to doing time here, nah, nobody wants to be here, you know? >> next on "lockup," the hidden messages and secret codes gangs use to communicate inside and outside pelican bay. in my world