The puzzle refers to a U-turn. Repentance consists of two things. 1) Turning around, or change of direction and 2) A change of mind. You cannot have a relationship with God without repentance. The willingness to turn from sin and to Christ is the turning that must occur to obtain eternal life. The Bible makes this very clear. Here are some resources on the subject.
What does the Bible say about repentance?
Videos About Repentance