This example visualizes a simple linear genome map, showing four genes as colored rectangles arranged along a horizontal axis. The green and red rectangles indicate forward and reverse orientations, respectively, with each gene labeled by name. The data comes from a local `data.json` file, loaded with `d3.json`, and each gene’s position and length are derived from its start and stop values. Using D3 v4, the code appends SVG `rect` elements for the genes and `text` labels, animating them into place with `transition().duration(1000).delay()` based on each gene’s start position.