BuildRight = function (x, y, width, height)
{
    if (height === undefined) { height = width; }

    //  90 degree angle
    var x1 = x;
    var y1 = y;

    var x2 = x;
    var y2 = y - height;

    var x3 = x + width;
    var y3 = y;

    return new Triangle(x1, y1, x2, y2, x3, y3);
}
Builds a right triangle, i.e. one which has a 90-degree angle and two acute angles.

@function Phaser.Geom.Triangle.BuildRight
@since 3.0.0

@param {number} x - The X coordinate of the right angle, which will also be the first X coordinate of the constructed Triangle.
@param {number} y - The Y coordinate of the right angle, which will also be the first Y coordinate of the constructed Triangle.
@param {number} width - The length of the side which is to the left or to the right of the right angle.
@param {number} height - The length of the side which is above or below the right angle.

@return {Phaser.Geom.Triangle} The constructed right Triangle.