For the past few years, the Functions Group at Berkeley 1 has been developing computer-based microworlds, collectively called GRAPHER, for exploring aspects of mathematical functions and graphs. We began by asking how we could harness computational technology to help students understand some complex mathematical ideas, to help them "see" some things that are difficult to grasp conceptually. The result was a pilot version of a computer-based environment focusing on the multiple connections among and multiple representations of graphs and the algebraic formulas that generate them.