diff --git a/libs/geom/include/psemek/geom/contains.hpp b/libs/geom/include/psemek/geom/contains.hpp
index c59eacff..3fb65f00 100644
--- a/libs/geom/include/psemek/geom/contains.hpp
+++ b/libs/geom/include/psemek/geom/contains.hpp
@@ -25,7 +25,7 @@ namespace psemek::geom
 	}
 
 	template <typename T>
-	bool contains(triangle<point<T, 2>> const & t, point<T, 2> const & p)
+	bool contains(simplex<point<T, 2>, 2> const & t, point<T, 2> const & p)
 	{
 		return true
 			&& orientation(t[0], t[1], p) != sign_t::negative
diff --git a/libs/geom/include/psemek/geom/simplex.hpp b/libs/geom/include/psemek/geom/simplex.hpp
index 977548d5..39483864 100644
--- a/libs/geom/include/psemek/geom/simplex.hpp
+++ b/libs/geom/include/psemek/geom/simplex.hpp
@@ -29,20 +29,10 @@ namespace psemek::geom
 	simplex(Args ...) -> simplex<std::common_type_t<Args...>, sizeof...(Args) - 1>;
 
 	template <typename Point>
-	struct segment
-		: simplex<Point, 1>
-	{};
+	using segment = simplex<Point, 1>;
 
 	template <typename Point>
-	segment(Point, Point) -> segment<Point>;
-
-	template <typename Point>
-	struct triangle
-		: simplex<Point, 2>
-	{};
-
-	template <typename Point>
-	triangle(Point, Point, Point) -> triangle<Point>;
+	using triangle = simplex<Point, 2>;
 
 	template <typename Stream, typename Point, std::size_t K>
 	Stream & operator << (Stream & os, simplex<Point, K> const & s)