Holy Text Dissections: Genesis 4

There's not much to say about this one, except about God accepting only Abel's sacrifice(WTF ya damn jackass) and about the Mark of Cain(How do you suffer vengeance 7 times from killing someone? Do you die then come back to life and get killed again 7 times?) Same for Lamech about the 77 times vengeance thing, and how the hell does killing 2 people equal 77? Would 3 be 777? Why is the vengeance exponential? And how does that fit into fundie views on the death penalty?