The three crosses represent the triune aspects of a human being created in the image of a triune God. The violent, angry, cursing thief on one side represents our sinful flesh that dwells inside us and compulsively urges us toward sin and away from life and God. Jesus on the next cross represents the new nature, the new heart that God implants in us that is perfect and untainted in motives and desires. The third cross represents our will which is choosing which of the other two he will embrace and join. He starts out with the fallen attitude of the flesh but the longer he observes the compassion and forgiveness and holiness of Jesus under overwhelming pressure and abuse from the flesh and all of Satan's forces, he is forced to decide whether to accept His grace and cast himself on God's mercy or to join the flesh in accusing God for all the suffering and injustice around him.