This was something I had absolutely no knowledge of until I read about this at Jason Kottke’s blog — which is a must-read by the way. Many ancient cultures used a variety of methods to create 3D physical representations of information they needed to know, like the one below, which is a visualization of ocean wave patterns created by Micronesians in the Marshall Islands. They would apparently pass these on from person to person and memorize them before heading out to sea in their boats. Straight sticks represent regular currents, curved sticks are ocean swells and seashells are islands.
Kottke also writes about how the Yakima tribe of native Americans used strings of hemp tied into balls as a kind of visual or tactile journal of their lives. So every major event was represented by a knot, a bead, or a shell. It was called an Ititamat or a counting-the-days ball or just a “time ball,” and it allowed the owner to recall specific events and times merely by touching and unwinding it. Those who lived long lives might have several, and when they passed away, the balls were buried with them.