I brought these out last week because we've started having snow and when we are outside we always look for tracks. I originally photo copied the tracks from another lesson and made the cards by finding pictures in magazines and laminating. We lay out the large tracks with pictures and name the animals, then find the smaller set and match it to the picture cards. One day we made our own foot print tracks on paper with paint, I cut one out and added it with a picture of my daughter to the lesson. Now we have human "tracks" as well.