diff --git a/src/3_snap_to_sphere.tes b/src/3_snap_to_sphere.tes
index 873e025..0e2a1b6 100644
--- a/src/3_snap_to_sphere.tes
+++ b/src/3_snap_to_sphere.tes
@@ -35,10 +35,15 @@ void main()
   // (so before model, view, proj are applied)
   
   /////////////////////////////////////////////////////////////////////////////
-  // Replace with your code 
+  // Replace with your code
+  // Based on:
+  // https://learnopengl.com/Guest-Articles/2021/Tessellation/Tessellation
+  sphere_fs_in = normalize(interp_pos.xyz);
+  view_pos_fs_in = view * model(is_moon, animation_seconds) * vec4(sphere_fs_in, 1.0);
+  normal_fs_in = normalize(mat3(view * model(is_moon, animation_seconds)) * sphere_fs_in);
+  pos_fs_in = proj * view_pos_fs_in;
 
-
-  gl_Position = interp_pos;
+  gl_Position = pos_fs_in;
   /////////////////////////////////////////////////////////////////////////////
 }