I think walking and thinking is a very natural thing to do. For one thing, it takes you away from all of the distractions in your life. It gives you a time to concentrate on the subject you would like to consider. I don't think t hat laughing at a thought is strange. What you are thinking can elicit the same responses as when you are conversing with someone else. Often people make facial expressions in response to what they are thinking. Not much of a difference to laugh over the same issue. This is an interesting subject. Thanks for bringing it up.