diff --git a/obj/quad_upper_face_missing.obj b/obj/quad_upper_face_missing.obj
new file mode 100644
index 0000000..517cdc9
--- /dev/null
+++ b/obj/quad_upper_face_missing.obj
@@ -0,0 +1,14 @@
+# This file uses centimeters as units for non-parametric coordinates.
+v -0.500000 -0.500000 0.500000
+v 0.500000 -0.500000 0.500000
+v -0.500000 0.500000 0.500000
+v 0.500000 0.500000 0.500000
+v -0.500000 0.500000 -0.500000
+v 0.500000 0.500000 -0.500000
+v -0.500000 -0.500000 -0.500000
+v 0.500000 -0.500000 -0.500000
+f 1 2 4 3
+f 5 6 8 7
+f 7 8 2 1
+f 2 8 6 4
+f 7 1 3 5