. >> aaron yost was 11 years into his latest sentence when we met him at kern valley state prison in california. he says his problems stem from a near life-long abuse of drugs. >> i grew up with drugs. my parents were quote/unquote hippies. both my parents dropped acid. my mom's dead now from a drug overdose. when i was 9 years old, i was rolling joints for mom and dad. >> yost's life is now largely confined to this cell, which he shares with another inmate. >> i'm not comfortable with this. i don't like men, i like women, you know? and this, to me, it's disgusting. i'm still irritated. if i wake up in the morning, i'm agitated because i have to live with another man. >> now, the closest yost comes to female companionship is through his tattoos. some of which are too graphic to show on television. >> that's what i dream about, that's all i got. you know? >> i remember when we met aaron, the man was tattooed, incredibly inked. if one word describes him, it's intense, just full of energy. and i remember when my producer asked him, what's the daily routine? he just started right in on t

. >> today castellanos is concerned about a white inmate named aaron yost. >> watch out for this guy on the yard. he's calling the shots on the block for the whites. we're expecting something today, but we don't know. >> before coming to prison, yost was a drug addict with a burglary and attempted burglary on his record. when he was arrested for manufacturing methamphetamine in 1996, he fell under california's three strikes statute and got 35 years to life. >> that means i might possibly be eligible for parole in the year 2028. but i'm like 43 right now, and that's a lifetime away. it's an insane -- it's an insane, incredible amount of time to sit somebody who has no history of violence. i don't have violence on my record at all, none. >> but since coming to prison, yost has been repeatedly written up by the staff for violent behavior. >> it's predatory. prison is predatory. your necessities and your wants, right, run on a razor's edge, you know? when -- it's just an analogy, but when a pen all of a sudden has the value of a corvette, you'll live and die over it. >> for the past 2 1/

. >> at kern valley state prison in california, we met inmate aaron yost who participates in anotheret very common practice behind bars. tattooing. >> mine's art work. you know what i mean? i did this myself. >> where? >> in a cell like this. >> how? >> how? see this cassette player? i ripped the motor out of it, and i attach a tube to it with the needle, spin the needle back and forth. and i make the ink. burn plastic or baby oil, and the soot will go up. i collect the soot and mix it with shampoo to make a thick black ink. >> tattooing in prison is illegal and poses a variety of health risks, but we've met countless inmates who have gotten their ink both on the outside and inside. many tattoos represent gang affiliation and are documented by prison officials. most of the rest have a meaning all their own. >> what my trip is is physics. my tattoos represent it. the tattoo on the back of my leg says "quantum physics." i've got an atom on my hand. i study what the ultimate nature of reality is. it sooths me. it soothes me to try and figure out what i am, what all this is, what it's al