Dogs work off of body language, and scents, and sounds. Humans work off of body language, sounds, and words, both spoken and written. In fact, we humans take it a step further (if not more) and have symbols that aren't words, but still expected to mean things. Obviously, these things don't mean much, if anything, to dogs. But sometimes they catch their attention.
Last June, I wrote a post called The Things You Notice, where I talked about a red riding hood statue that was in a yard Elka and I frequently passed (now no longer there, sadly). Due to construction, we have a slightly different walk route lately, and today Elka noticed a Buddha statue in somebody's yard.