diff --git a/cruft/util/geom/tri.hpp b/cruft/util/geom/tri.hpp
index 970d3b20..b12049fc 100644
--- a/cruft/util/geom/tri.hpp
+++ b/cruft/util/geom/tri.hpp
@@ -9,6 +9,7 @@
 #pragma once
 
 #include "../point.hpp"
+#include "cruft/util/geom/segment.hpp"
 #include "sample/fwd.hpp"
 
 #include <cstddef>
@@ -67,6 +68,19 @@ namespace cruft::geom {
     };
 
 
+    ///////////////////////////////////////////////////////////////////////////
+    template <std::size_t S, typename T>
+    std::array<cruft::geom::segment<S,T>, 3>
+    edges (tri<S,T> const &t)
+    {
+        return {{
+            { t.a, t.b },
+            { t.b, t.c },
+            { t.c, t.a },
+        }};
+    }
+
+
     ///////////////////////////////////////////////////////////////////////////
     // n-dimensional triangle area
     template <std::size_t DimensionV, typename ValueT>