This example demonstrates three versions of an interactive barcode chart that visualizes event timestamps as vertical lines on a timeline, with buttons to add new data points using an exponential random interval generator. The first chart shows basic updates, the second addresses transition smoothing, and the third refines bar removal. Built with D3 v5, the code uses `d3.scaleTime`, `d3.timeDay`, and `d3.dispatch` for time-domain mapping and custom event handling, rendering SVG elements with enter/update selections and animated transitions. The dataset consists of JavaScript `Date` objects generated client-side.