We used them in my education too. Do you have the track?[1] It can help with the concrete/abstract correlation. [1] http://marcialmiller.com/wordpress/wp-cont

We used them in my education too. Do you have the track?[1] It can help with the concrete/abstract correlation. [1] http://marcialmiller.com/wordpress/wp-content/uploads/2011/01/Staircasesandrodtracks.jpg http://marcialmiller.com/wordpress/wp-content/uploads/2011/0...