A grid of small colored cells for each continent visualizes the growth of COVID-19 cases over time, with columns representing days and rows representing case counts. The visualization uses a dark background with a color scale from dark gray to red to encode increasing values, and includes an annotation highlighting a specific point of interest in China. The data is generated randomly using d3.v5, with each cell’s value derived from its predecessor, and the layout is built with SVG and HTML divs, while d3-annotation adds a callout circle for emphasis.