diff --git a/libs/geom/include/psemek/geom/ray.hpp b/libs/geom/include/psemek/geom/ray.hpp
index a26a743f..00e33e50 100644
--- a/libs/geom/include/psemek/geom/ray.hpp
+++ b/libs/geom/include/psemek/geom/ray.hpp
@@ -3,6 +3,8 @@
 #include <psemek/geom/vector.hpp>
 #include <psemek/geom/point.hpp>
 
+#include <iostream>
+
 namespace psemek::geom
 {
 
@@ -56,4 +58,11 @@ namespace psemek::geom
 		return res;
 	}
 
+	template <typename T, std::size_t N>
+	std::ostream & operator << (std::ostream & os, ray<T, N> const & r)
+	{
+		os << '[' << r.origin << ", " << r.direction << ']';
+		return os;
+	}
+
 }