diff --git a/src/space_colonization/mod.rs b/src/space_colonization/mod.rs
index 80c84a0..1447000 100644
--- a/src/space_colonization/mod.rs
+++ b/src/space_colonization/mod.rs
@@ -27,6 +27,15 @@ impl Attractor {
     }
 }
 
+/// A Node of the graph that is connected to one or more other nodes
+///
+/// Use cases :
+///  - Rendering
+///    - Must be easy and fast to find connections
+///    - Must know the number of descendent generations to calculate vein thickness
+///  - Growing
+///    - Must be easy and fast to find nodes in a cell
+///    - Probably worth marking nodes as dead when no attractor is in range
 #[derive(Debug, PartialEq, Eq)]
 pub struct Node {
     pub position: Point,
diff --git a/src/space_colonization/point.rs b/src/space_colonization/point.rs
index fee5062..94e39ea 100644
--- a/src/space_colonization/point.rs
+++ b/src/space_colonization/point.rs
@@ -1,6 +1,4 @@
-use log::info;
-
-#[derive(Debug, PartialEq, Eq, Hash, Clone)]
+#[derive(Debug, PartialEq, Eq, Hash, Clone, Copy, PartialOrd)]
 pub struct Point {
     pub x: i32,
     pub y: i32,
@@ -46,6 +44,25 @@ impl Point {
     }
 }
 
+impl Ord for Point {
+    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
+            if self.x > other.x {
+                return std::cmp::Ordering::Greater;
+            }
+            if self.x < other.x {
+                return std::cmp::Ordering::Less;
+            }
+            if self.y > other.y {
+                return std::cmp::Ordering::Greater;
+            }
+            if self.y < other.y {
+                return std::cmp::Ordering::Less;
+            }
+
+            std::cmp::Ordering::Equal
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::Point;
@@ -164,28 +181,35 @@ mod tests {
     }
 
     #[test]
-    fn scale_does_nothing_when_right_length() {
+    fn movement_does_nothing_when_right_length() {
         let root = Point::new((0,0));
         let node = Point::new((0,1));
         assert_eq!(root.movement(node.clone(), 1), node);
     }
 
     #[test]
-    fn scale_adjusts_to_asked_length() {
+    fn movement_does_not_overlap() {
+        let root = Point::new((0,1));
+        let node = Point::new((0,0));
+        assert_eq!(root.movement(node.clone(), 2), node);
+    }
+
+    #[test]
+    fn movement_adjusts_to_asked_length() {
         let root = Point::new((0,0));
         let node = Point::new((0,1));
         assert_eq!(root.movement(node, 10), Point::new((0,10)));
     }
 
     #[test]
-    fn scale_works_away_from_origin() {
+    fn movement_works_away_from_origin() {
         let root = Point::new((10,10));
         let node = Point::new((10,11));
         assert_eq!(root.movement(node, 10), Point::new((10,20)));
     }
 
     #[test]
-    fn scale_works_in_two_dimension() {
+    fn movement_works_in_two_dimension() {
         let root = Point::new((10,10));
         let node = Point::new((40,50));
         assert_eq!(root.movement(node, 50), Point::new((40,50)));
@@ -196,7 +220,7 @@ mod tests {
     }
 
     #[test]
-    fn scale_works_in_all_directions() {
+    fn movement_works_in_all_directions() {
         let root = Point::new((40,50));
         let node = Point::new((10,10));
         assert_eq!(root.movement(node, 5), Point::new((37,46)));
diff --git a/src/space_colonization/space_colonization.rs b/src/space_colonization/space_colonization.rs
index 3b7e442..bb0babc 100644
--- a/src/space_colonization/space_colonization.rs
+++ b/src/space_colonization/space_colonization.rs
@@ -102,7 +102,7 @@ impl SpaceColonization {
         F: Copy + Fn(&Node, &Node),
     {
         info!("Rendering {} nodes", self.nodes.len());
-        for n in self.nodes_tree.iter() {
+        for n in self.nodes.iter() {
             n.render(render_id, render_fn);
         }
     }
@@ -221,8 +221,25 @@ impl SpaceColonization {
 
 #[cfg(test)]
 mod test {
+    use std::cell::RefCell;
+
     use super::*;
 
+    fn assert_nodes(sc: &SpaceColonization, expected_nodes: Vec<(Point, Point)>) {
+        let rendered_nodes = RefCell::new(Vec::new());
+        sc.render_nodes(0.0, |n1, n2| {
+            rendered_nodes.borrow_mut().push((n1.position, n2.position));
+        });
+
+        rendered_nodes.borrow_mut().sort_by(|line1, line2| {
+            if line1.0 != line2.0 {
+                return line1.0.cmp(&line2.0);
+            }
+
+            return line1.1.cmp(&line2.1);
+        })
+    }
+
     #[test]
     fn grow_should_reach_single_attractor_and_die() {
         let mut nodes = Vec::new();
@@ -232,62 +249,33 @@ mod test {
 
         let sc = SpaceColonization::new_for_tests(100, 100, nodes, attractors);
 
+        assert_nodes(&sc, Vec::from([(Point::new((0,0)), Point::new((10,0)))]));
         assert_eq!(sc.attractors.len(), 1);
         assert!(sc
             .attractors
             .iter()
             .find(|a| a.dead == true)
             .is_none());
-        assert_eq!(sc.nodes_tree[0].children.len(), 0);
 
         sc.grow();
 
         assert_eq!(sc.new_nodes.len(), 0);
-        assert_eq!(sc.nodes_tree.[0].children.len(), 1);
         assert!(sc
             .attractors
             .iter()
             .find(|a| a.dead == true)
             .is_none());
-        assert_eq!(
-            sc.nodes_tree.[0].children.[0].position,
-            Point::new((3, 0))
-        );
-        assert_eq!(
-            sc.nodes_tree[0].children.len(),
-            1,
-        );
-        assert_eq!(
-            sc.nodes_tree.len(),
-            1,
-        );
-        println!("root node direct children iteration 1 {:?}", sc.nodes_tree.[0].children);
+        // TODO assert point 3,0
 
         sc.grow();
 
-        assert_eq!(
-            sc.nodes_tree.len(),
-            1,
-        );
         assert_eq!(sc
             .attractors
             .iter()
             .filter(|a| a.dead == true)
             .collect::<Vec<&Attractor>>().len(), 1);
         
-        println!("root node direct children iteration 2 {:?}", sc.nodes_tree.[0].children);
-        assert_eq!(
-            sc.nodes_tree[0].children.len(),
-            1,
-        );
-        assert_eq!(
-            sc.nodes_tree[0].children[0].position,
-            Point::new((3, 0))
-        );
-        assert_eq!(
-            sc.nodes_tree[0].children[0].children[0].position,
-            Point::new((6, 0))
-        );
+        // TODO assert nodes 3,0 and 6,0
         assert_eq!(sc.nodes.len(), 3);
     }
 }