code: function shear(shx, shy) {
      return {
          a: 1, c: shx, e: 0,
          b: shy, d: 1, f: 0
      };
  }
docs: Calculate a shear matrix
  @param shx Shear on axis x
  @param shy Shear on axis y
  @returns {{a: number, b: number, c: number, e: number, d: number, f: number}} Affine matrix