function rectsOverlap(a, b)
        {
            return segmentsOverlap(a[0], a[0] + a[2], b[0], b[0] + b[2]) && segmentsOverlap(a[1], a[1] + a[3], b[1], b[1] + b[3]);
        }
@param {!Array.<number>} a
@param {!Array.<number>} b
@return {boolean}