Periodically throughout computer history there emerges a "pinch point," a single moment where many prior technologies converge, and upon which many subsequent technologies depend. Herman Hollerith's 1890 census tabulator is one well-known instance. Another, somewhat lesser-known, is Ivan Sutherland's "Sketchpad," developed at MIT in the early 1960s, running on the transistor-based TX-2 computer. Nearly all interactive graphics applications today can trace their roots back to this pivotal demonstration. It's considered the first graphical user interface (GUI) at a time when computer graphics of ANY sort were virtually unheard of, let alone the notion that computers could be applied to both artistic and technical purposes. Part 1: an interview with professor Steven Coons., Part 2: demonstrating the 2D capabilities of Sketchpad, including vector scaling and instances., Part 3: demonstrating the 3D capabilities of Sketchpad.