If you're a born collector, you can probably never go for a walk in the woods or on the beach without putting something in your pocket. Not everything you find might be worthwhile, and sometimes it’s fun to restrict yourself in what you pick up. Maybe you can put stones in your pocket that resemble the face of someone you know, or a celebrity. It's also a great game to play with children who didn’t like going for long walks as well as with friends with the same collector mania. In any case, it gets your imagination going and puts a smile on your face. And all it requires is a black marker, which you can easily pop in your pocket.