code: function getCoordinates(location) {
    var tile_width = 40;
    var x = location.r * tile_width;
    var y = location.c * tile_width;
    return {x: x, y: y};
  }
docs: Convert an array location to a point representing the top-left
  corner of the tile in global coordinates.
  @private
  @param {ArrayLoc} location - The array location to get the
  coordinates for.
  @return {MPPoint} - The coordinates of the tile.