Matrix3i m1;
m1 << 1, 2, 3, 4, 5, 6, 7, 8, 9;
cout << m1 << endl << endl;
Matrix3i m2 = Matrix3i::Identity();
m2.block(0, 0, 2, 2) << 10, 11, 12, 13;
cout << m2 << endl << endl;
Vector2i v1;
v1 << 14, 15;
m2 << v1.transpose(), 16, v1, m1.block(1, 1, 2, 2);
cout << m2 << endl;