These are the slides I made for a presentation on programmatically drawing parallel lines on a Web Mercator projection map. Click through the slides below, and click the buttons on each slide to animate the lines onto the map. On each slide, advance using the "Next" button in the top right.
This website doesn't look great on a phone, I've added buttons to hide the card text to reveal more of the map, but try it out on a larger device if there is hidden content.