In the last part, we defined some variables that we will use for generating terrain. First we start off by selecting the canvas element from our html using the DOM document method called querySelector. Next we resize this via resizeCavas() function that we define later to fill the body of html. Now we need a drawing object for canvas. The getContext() is a built-in HTML object, with properties and methods for drawing. We have also created a points array to store the random points generated for the terrain.