--- a/rust/integral-geometry/src/lib.rs	Mon Nov 05 19:56:28 2018 +0300
+++ b/rust/integral-geometry/src/lib.rs	Mon Nov 05 20:22:09 2018 +0300
@@ -464,11 +464,21 @@
         (&self.vertices[..self.edges_count()]).iter()
     }
 
-    pub fn iter_mut<'a>(&'a mut self) -> impl Iterator<Item = &mut Point> + 'a {
+    fn iter_mut<'a>(&'a mut self) -> impl Iterator<Item = &mut Point> + 'a {
         let edges_count = self.edges_count();
         (&mut self.vertices[..edges_count]).iter_mut()
     }
 
+    pub fn for_each<F>(&mut self, f: F)
+        where F: (Fn(&mut Point))
+    {
+        if !self.vertices.is_empty() {
+            self.iter_mut().for_each(f);
+            let edges_count = self.edges_count();
+            self.vertices[edges_count] = self.vertices[0]
+        }
+    }
+
     pub fn iter_edges<'a>(&'a self) -> impl Iterator<Item = Line> + 'a {
         (&self.vertices[0..self.edges_count()])
             .iter()