John has enrolled in an art class and is learning how to convey depth perception

John has enrolled in an art class and is learning how to convey depth perception in his drawings. John had thought about Gestalt principles of vision perception. He claims that these principles are applicable only to textbook illustrations and therefore are not very useful.
Describe the three things John can do in his drawings to convey depth convincingly.
Explain how Gestalt principles can be applied to everyday and real-life vision perceptions.
Consider a community where most people have achromatopsia.
Describe this vision disorder and its causes.
Based on what you know about rod and cone vision, explain how the community could be modified to compensate for this vision disorder.
** PLease inlcude 3 follow-up questions to further the discussion on the topic