diff --git a/doc/snippets/MatrixBase_setIdentity.cpp b/doc/snippets/MatrixBase_setIdentity.cpp
new file mode 100644
index 0000000..4fd0aa2
--- /dev/null
+++ b/doc/snippets/MatrixBase_setIdentity.cpp
@@ -0,0 +1,3 @@
+Matrix4i m = Matrix4i::Zero();
+m.block<3,3>(1,0).setIdentity();
+cout << m << endl;