These are studies of types in the Bible. Types are comparisons saying something is "like" or "as" something else.  In the Bible, these are called "similitudes."  This is one of God's teaching methods to compare things in His creation.  For instance, Jesus Christ said men were like sheep.  By studying sheep we can learn a lot about men.  Paul said sin was like leaven, so we can learn about sin by studying leaven.  These comparisons are numerous throughout the Bible.

• The Altar of Incense as a type of Prayer

• The Ark as a type of Jesus Christ