diff --git a/doc/snippets/MatrixBase_extract.cpp b/doc/snippets/MatrixBase_extract.cpp
new file mode 100644
index 0000000..c96220f
--- /dev/null
+++ b/doc/snippets/MatrixBase_extract.cpp
@@ -0,0 +1,13 @@
+#ifndef _MSC_VER
+  #warning deprecated
+#endif
+/* deprecated
+Matrix3i m = Matrix3i::Random();
+cout << "Here is the matrix m:" << endl << m << endl;
+cout << "Here is the upper-triangular matrix extracted from m:" << endl
+     << m.part<Eigen::UpperTriangular>() << endl;
+cout << "Here is the strictly-upper-triangular matrix extracted from m:" << endl
+     << m.part<Eigen::StrictlyUpperTriangular>() << endl;
+cout << "Here is the unit-lower-triangular matrix extracted from m:" << endl
+     << m.part<Eigen::UnitLowerTriangular>() << endl;
+*/
\ No newline at end of file