code: public Matrix3d scaling(double factor) {
          m00 = factor;
          m01 = 0.0;
          m02 = 0.0;
          m10 = 0.0;
          m11 = factor;
          m12 = 0.0;
          m20 = 0.0;
          m21 = 0.0;
          m22 = factor;
          return this;
      }
docs: Set this matrix to be a simple scale matrix, which scales all axes uniformly by the given factor.
  <p>
  The resulting matrix can be multiplied against another transformation
  matrix to obtain an additional scaling.
  <p>
  In order to post-multiply a scaling transformation directly to a
  matrix, use {@link #scale(double) scale()} instead.
  
  @see #scale(double)
  
  @param factor
  the scale factor in x, y and z
  @return this