Some authors caution that many students with strong religious backgrounds often balk at the idea of developing an ethical system because they feel they already have one in place and have no intention of subjecting it to any scrutiny. I have included mine, adapted from The Greater Cleveland Science Project. Whatever method is used, the key is to turn it into a self-study. I use it as an informal, non-graded activity which works very well at the beginning of a school year. Ask for descriptions.
Most students see only the young woman.
Tell them that some people see only an old woman. Wait until they see her. Develop an operational definition of perception. Show and discuss the optical illusions enclosed. Conflicting perceptions often come into play in court cases.