Pause in a park or field in summer and look out across the grass and you’ll see a multitude of thin, earthy tracks breaking up the swaths of green like shatters in a pane of glass. These are most commonly known as desire paths – although other names include cow paths, desire lines, pirate paths or social trails – and are created when humans (or animals) are drawn in the same direction over and over, flattening the grass and eventually wearing it away.