Liza explains that our brain processes information from our senses and makes conclusions (perceptions) about our environment. When these perceptions are wrong, this is an illusion. They show a few examples of an optical illusion.

Temple, an autistic student, watches a short film on optical illusions and is immediately intrigued by it. She sets out to achieve the effects in the movie and does so after much persistence.

Bright Eyes keeps trying to form words and is very responsive to human stimuli. The apes possess many human-like traits

Chris and Martin find out the hidden power of zebra stripes.

Jerry Andress explains several optical illusions and suggests that the discrepancy between our perception and the reality is not a mistake of the brain; the brain tried its best to map out the reality with whatever information it had.