diff --git a/Tetrahedrons/MVec4D.cs b/Tetrahedrons/MVec4D.cs
index ddc59be..eb9bdd5 100644
--- a/Tetrahedrons/MVec4D.cs
+++ b/Tetrahedrons/MVec4D.cs
@@ -61,6 +61,9 @@ namespace Tetrahedrons
          }
       }
 
+      public Vector4d V4 => new Vector4d(X, Y, Z, W);
+      public Vector3d V3 => new Vector3d(X, Y, Z);
+
       #region Swizzle
 
       public double Yx
diff --git a/Tetrahedrons/TetrahedronWindow.cs b/Tetrahedrons/TetrahedronWindow.cs
index 0e26716..b95f896 100644
--- a/Tetrahedrons/TetrahedronWindow.cs
+++ b/Tetrahedrons/TetrahedronWindow.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Drawing;
+using System.Drawing.Printing;
 using System.Net.Mail;
 using System.Security;
 using OpenTK;
@@ -15,8 +16,10 @@ namespace Tetrahedrons
       private Matrix4 _proj3d;
       private Matrix4 _view;
 
-      Vector3d a = Vector3d.UnitX;
-      Vector3d b = Vector3d.UnitY;
+      MVec4D a = MVec4D.UnitX;
+      MVec4D b = MVec4D.UnitY;
+      MVec4D v = MVec4D.Vec1(1, 1, 0, -1);
+      MVec4D t = MVec4D.Vec1(0, 0, 0, 1);
 
       protected override void OnLoad(EventArgs e)
       {
@@ -25,7 +28,8 @@ namespace Tetrahedrons
          X = (DisplayDevice.Default.Width - Width) / 2;
          Y = (DisplayDevice.Default.Height - Height) / 2;
 
-         _view = Matrix4.LookAt(Vector3.Zero, -new Vector3(1, .6f, 1f), Vector3.UnitZ);
+         _view = Matrix4.LookAt(Vector3.Zero, -new Vector3(1, 1, 1), Vector3.UnitZ);
+
       }
 
       protected override void OnRenderFrame(FrameEventArgs e)
@@ -35,7 +39,9 @@ namespace Tetrahedrons
          GL.Viewport(ClientRectangle);
 
          GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit);
+         GL.Enable(EnableCap.DepthTest);
          GL.PointSize(10f);
+         GL.LineWidth(3f);
 
          GL.PushMatrix();
 
@@ -44,11 +50,41 @@ namespace Tetrahedrons
          GL.MatrixMode(MatrixMode.Modelview);
          GL.LoadMatrix(ref _view);
 
+         GL.Disable(EnableCap.DepthTest);
          GL.Begin(PrimitiveType.TriangleStrip);
-         GL.Vertex3(-a - b);
-         GL.Vertex3(-a + b);
-         GL.Vertex3(a - b);
-         GL.Vertex3(a + b);
+         GL.Color3(1d, 1, 1);
+         GL.Vertex3((-a - b).V3);
+         GL.Vertex3((-a + b).V3);
+         GL.Vertex3((a - b).V3);
+         GL.Vertex3((a + b).V3);
+         GL.End();
+         GL.Enable(EnableCap.DepthTest);
+         
+         GL.Begin(PrimitiveType.Lines);
+         GL.Color3(1d,0,0); GL.Vertex3(0,0,0); GL.Vertex3(1,0,0);
+         GL.Color3(0,1d,0); GL.Vertex3(0,0,0); GL.Vertex3(0,1,0);
+         GL.Color3(0,0,1d); GL.Vertex3(0,0,0); GL.Vertex3(0,0,1);
+         GL.End();
+
+         var B = MVec4D.UnitXyz;
+         var bt = B ^ t;
+         var bv = B ^ v;
+         var alph = bt / bv ?? MVec4D.Zero;
+         var dt = alph * v;
+         var p = t - dt;
+
+         Console.Out.WriteLine("p = {0}", p);
+
+         GL.Begin(PrimitiveType.Lines);
+         GL.Color3(.5 + t.W/4, 0, .5 - t.W/4);
+         GL.Vertex3(t.V3);
+         GL.Color3(.5 + (t + v).W/4, 0, .5 - (t + v).W/4);
+         GL.Vertex3((t + v).V3);
+         GL.End();
+
+         GL.Begin(PrimitiveType.Points);
+         GL.Color3(0d, 0, 1);
+         GL.Vertex3(p.V3);
          GL.End();
 
          SwapBuffers();
@@ -59,6 +95,12 @@ namespace Tetrahedrons
          base.OnUpdateFrame(e);
 
          _proj3d = Matrix4.CreateOrthographic(6, 6f * Height / Width, -2, 2);
+
+         var rv = MVec4D.Rotor(e.Time, MVec4D.UnitXy);
+         v = rv * v * !rv;
+
+         var rt = MVec4D.Rotor(e.Time / 4, MVec4D.UnitZw);
+         t = rt * t * !rt;
       }
    }
 }
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