The themes of adult coloring books are usually intricate and centered more around adult images, not your childhood counterparts that included bunnies, super heroes, and farm animals. You would expect to see geometric patterns, psychedelic patterns reminiscent of doodle art type pages, fantasy images including angels, dragons, goddesses and mermaids, and ancient designs of religious and spiritual nature.
The repetitive, low-stress, and "no brainer" act of color lends itself to relaxation. The calming effects not only helps to reduce stress levels, but also can help to bring you back to your youth. The awesome part is that anyone can do it will no skill set required! Grab a crayon and you are good to go. You can make it even more enjoyable and have your kids or grandkids color with you. Depending on the age of the young ones they may be interested in the adult coloring books, others still wanting to color a cow, astronaut, or pretty flower arrangement.