diff --git a/README.md b/README.md
index 780c941..6260403 100644
--- a/README.md
+++ b/README.md
@@ -21,6 +21,10 @@ Simple demand assignment network calculator.
     dl c1000 1010
     dt c1000 1010 1020
 
+## Notes
+
+* Centroids have their own namepsace, separate from nodes
+
 # Installation
 
 * git clone the repo
diff --git a/src/main/scala/gncc/network/Network.scala b/src/main/scala/gncc/network/Network.scala
index 8c375a9..284832c 100644
--- a/src/main/scala/gncc/network/Network.scala
+++ b/src/main/scala/gncc/network/Network.scala
@@ -31,6 +31,10 @@ trait Network {
   def al(i: Int, j: Int): Reason
   def addLink(i: Int, j: Int) = al(i, j)
   def +(i: Int, j: Int) = al(i, j)
+
+  def at(i: Int, j: Int, k: Int): Reason
+  def addTurn(i: Int, j: Int, k: Int) = at(i,j,k)
+  def +(i: Int, j: Int, k: Int) = at(i,j,k)
 }
 
 class DefaultNetwork extends Network {
@@ -39,11 +43,19 @@ class DefaultNetwork extends Network {
 
   val nodes = new HashSet[Node]
   val links = new HashSet[Link]
+  val turns = new HashSet[Turn]
 
   def getNode(id: Int) = {
     nodes.findEntry(Node(id))
   }
 
+  def getLink(i: Int, j: Int): Option[Link] = {
+    links.findEntry(Link(i, j))
+  }
+  def getLink(i: Node, j: Node): Option[Link] = {
+    getLink(i.id, j.id)
+  }
+
   def an(id: Int): Reason = {
     if (nodes.add(Node(id)))
       Success
@@ -63,6 +75,17 @@ class DefaultNetwork extends Network {
     }
   }
 
+  def at(i: Int, j: Int, k: Int): Reason = {
+    val turnLinks = (getLink(i, j), getLink(j, k))
+
+    turnLinks match {
+      case (Some(i), Some(j)) => if(turns.add(Turn(i, j))) Success else TurnExists
+      case (None, None) => NoNodesAreLinked
+      case (None, _) => IJAreNotLinked
+      case (_, None) => JKAreNotLinked
+    }
+  }
+
   // Currently using this for debugging
   override def toString = {
     "Nodes: " + nodes.toString + "Links: " + links.toString
@@ -72,4 +95,4 @@ class DefaultNetwork extends Network {
 abstract class NetworkElement
 case class Node(id: Int) extends NetworkElement
 case class Link(iNode: Int, jNode: Int) extends NetworkElement
-case class Turn(iLink: Int, jLink: Int) extends NetworkElement
\ No newline at end of file
+case class Turn(iLink: Link, jLink: Link) extends NetworkElement
\ No newline at end of file
diff --git a/src/main/scala/gncc/network/package.scala b/src/main/scala/gncc/network/package.scala
index b10bda2..4fc1e11 100644
--- a/src/main/scala/gncc/network/package.scala
+++ b/src/main/scala/gncc/network/package.scala
@@ -18,7 +18,7 @@ package gncc
 package object network {
   object NetworkOperationStatus extends Enumeration {
     type Reason = Value
-    val Success, NodeExists, LinkExists, TurnExists, InvalidNodes, INodeInvalid, JNodeInvalid, KNodeInvalid, ILinkInvalid, JLinkInvalid = Value
+    val Success, NodeExists, LinkExists, TurnExists, InvalidNodes, INodeInvalid, JNodeInvalid, KNodeInvalid, IJAreNotLinked, JKAreNotLinked, NoNodesAreLinked = Value
   }
 }
 
diff --git a/src/test/scala/network/NetworkSuite.scala b/src/test/scala/network/NetworkSuite.scala
index 8765501..c06c8e7 100644
--- a/src/test/scala/network/NetworkSuite.scala
+++ b/src/test/scala/network/NetworkSuite.scala
@@ -29,6 +29,7 @@ class NetworkSuiteSpec extends WordSpec with ShouldMatchers {
         network.addNode(1) should be (Success)
         network + 2 should be (Success)
         network an 3 should be (Success)
+        network + 4 should be (Success)
       }
 
       "while they produce an error if you add an existing one" in {
@@ -40,9 +41,10 @@ class NetworkSuiteSpec extends WordSpec with ShouldMatchers {
       "links are easy to add" in {
         network.addLink(1, 2) should be (Success)
         network al (2, 3) should be (Success)
+        network + (4, 3) should be (Success)
       }
 
-      "but error when we add one that already exists" in {
+      "error when we add one that already exists" in {
         network.addLink(1, 2) should be (LinkExists)
       }
 
@@ -58,5 +60,27 @@ class NetworkSuiteSpec extends WordSpec with ShouldMatchers {
         network.addLink(11,11) should be (InvalidNodes)
       }
     }
+
+    "finally, atop links we can add turns" that {
+      "turns require three nodes" in {
+        network at(1,2,3) should be (Success)
+      }
+
+      "error when the first two nodes are not linked" in {
+        network at(1,4,3) should be (IJAreNotLinked)
+      }
+
+      "error when the second two nodes are not linked" in {
+        network at(1,2,4) should be (JKAreNotLinked)
+      }
+
+      "error when all nodes are invalid" in {
+        network at(1,3,4) should be (NoNodesAreLinked)
+      }
+
+      "error when we try to add the same turn over again" in {
+        network + (1,2,3) should be (TurnExists)
+      }
+    }
   }
 }
\ No newline at end of file