Old Testament symbolism-the blood of Christ that redeems those who believe is the New Covenant through the cross. That is the gospel that God so loved the world that Christ died for our sins if we repent and believe. The Old Covenant of Moses and the Law carried the same symbolism through the Passover Lamb and the tabernacle.
The symbols are to stir up belief through the patterns that all people, and certainly autists, would recognize and hearts led to realize that God is the same yesterday today and forever and that Christ was Plan A from the beginning of time. Take the opportunity to believe in Jesus Christ today anons! :)