diff --git a/eo/tutorial/Lesson3/real_value.h b/eo/tutorial/Lesson3/real_value.h
new file mode 100644
index 00000000..7fe002b6
--- /dev/null
+++ b/eo/tutorial/Lesson3/real_value.h
@@ -0,0 +1,20 @@
+#include <vector>
+//-----------------------------------------------------------------------------
+/** Just a simple function that takes an vector<double> and sets the fitnes 
+    to the sphere function. Please use doubles not float!!!
+    @param _ind A floatingpoint vector 
+*/
+
+// INIT
+double real_value(const std::vector<double>& _ind)
+{
+  double sum = 0;
+  for (unsigned i = 0; i < _ind.size(); i++)
+      {
+	  sum += _ind[i] * _ind[i];
+      }
+  return sum;
+}
+
+
+