Hi David!
The questions you want to ask yourself 1) will it be distracting or offensive for some students, and 2) will it offer a positive environment for learning?
But using in a combination that students are learning the class topic as well as experiencing a fun, peacful environmnet is certainly acceptable. Moderation is probably the key to using the art "in-contrast".
Keep up the good work!
Jane Davis
Ed107 Facilitator
