If you want to draw them, that's one answer. You also can take digital photos of the real thing and run them through a program like imageSynth. In addition, you can download such textures free. The Dundjinni site (http://www.dundjinni.com was mentioned above. Another good address is http://www.rpgmapshare.com. If you want specimens made from digital photos of real European cobblestone, you can download our free and open textures and fills set. Go to: http://www.vintyri.org/vintyri/vccindex.htm