code: function (x, y, z, distance) {
              /**
               * The normal vector to the plane.
               * @type {Vec3}
               */
              this.normal = new Vec3(x, y, z);
  
              /**
               * The plane's distance from the origin.
               * @type {Number}
               */
              this.distance = distance;
          }
docs: Constructs a plane.
  This constructor does not normalize the components. It assumes that a unit normal vector is provided.
  @alias Plane
  @constructor
  @classdesc Represents a plane in Cartesian coordinates.
  The plane's X, Y and Z components indicate the plane's normal vector. The distance component
  indicates the plane's distance from the origin relative to its unit normal.
  The components are expected to be normalized.
  @param {Number} x The X coordinate of the plane's unit normal vector.
  @param {Number} y The Y coordinate of the plane's unit normal vector.
  @param {Number} z The Z coordinate of the plane's unit normal vector.
  @param {Number} distance The plane's distance from the origin.