This multitouch visualization maps each finger contact to a colored circle on an SVG canvas, with touches tracked by identifier. The example uses D3’s `d3.touches` API to capture touch events and `d3.event` to prevent default scrolling. Newly detected touches enter with an elastic scaling animation via `transition.attr("r", …)`, while removed touches shrink and exit. Circle positions update directly from touch coordinates, and color assignment uses `d3.scale.category10`. The code relies on touch-supporting browsers, such as iOS Safari, to dispatch the appropriate events.