1. Topic
2. Converging
   1. Convex
   2. image
      1. virtual
      2. only when object inside focus
   3. f is positive
3. Diverging
   1. Concave
   2. image
      1. virtual
      2. direct
      3. diminished
   3. f is negitive
4. Laws
   1. Topic
   2. Topic
   3. Power of lense
   4. 2 lenses in contact