public Matrix3f mult(Matrix3f mat) {
        return mult(mat, null);
    }
Multiplies with the argument matrix and returns the product as a new
instance. The current instance is unaffected.

<p>Note that matrix multiplication is noncommutative, so generally
q * p != p * q.

@param mat the right factor (not null, unaffected)
@return {@code this} times {@code mat} (a new Matrix3f)
jme3-core/src/main/java/com/jme3/math/Matrix3f.java