               // the pixel width of grid lines
   *     strokeStyle: '#777777',                 // colour of grid lines
   *     millisPerLine: 1000,                    // distance between vertical grid lines
   *     sharpLines: false,                      // controls whether grid lines are 1px sharp, or softened
   *     verticalSections: 2,                    // number of vertical sections marked out by horizontal grid lines
   *     borderVisible: true                     // whether the grid lines trac