The rules are - no rules.
Odd Ball Photos are those great photos that you take which really don’t seem to fit into a common category. We’ve all taken them and like them, because we just can’t hit delete and get rid of them. If you have any of those type of photos, this challenge is for you.
Oddball: noun a person or thing that is atypical, bizarre, eccentric, or nonconforming
adjective whimsically free-spirited; eccentric; atypical
July 2018 - Toronto ON
I think this billboard falls under the adjective "whimsically" fun.