The best-known chiasmus, which many people still recall, was delivered by President John F. Kennedy, who stated, “Ask not what your country can do for you; ask what you can do for your country.” That compound sentence is called an ABC chiasmus. Other forms of chiasmus are longer and more complex. We often see that the point and focus of a complex chiasmus are revealed in the center. For example, see Mark 1:21-28 where the central idea is that Jesus is the Holy One of God. Later in that chapter, Jesus heals a leper, which is also a chiasmus.
A more simple chiasmus in Mark 2:27 is here.
In Mark 4, the parable of the Sower is here.
In Mark 6, the story about the heading of John The Baptist is here.