[spoilers] Lucas and his tattoos

[HellsBells]

Interesting comparison between Jo and Lucas, Byatil. We see the emotional damaged done to Jo and the help she received to over come those problems. But in Lucas's case he appears to have been left alone to deal with things on his own, indeed it was Lucas that pointed the team towards Jo's need for help.
I have always believed that the codes within the tattoos were important either to Lucas (to help him remember specific events or thoughts) or to other prisoners with whom he made alliances with in prison.