diff --git a/testdata/drc/drcSimpleTests_19.drc b/testdata/drc/drcSimpleTests_19.drc
index e92ef5d58..f2b05ba56 100644
--- a/testdata/drc/drcSimpleTests_19.drc
+++ b/testdata/drc/drcSimpleTests_19.drc
@@ -9,18 +9,27 @@ l2 = input(2, 0)
 
 l1.output(1, 0)
 l2.output(2, 0)
+
 l1.space(3.0, transparent, projection).output(100, 0)
 l1.space(3.0, shielded, projection).output(101, 0)
+# NOTE: for two-layer checks, the *second* layer
+# shields, but not the first one
 l2.separation(l1, 3.0, transparent, projection).output(110, 0)
 l2.separation(l1, 3.0, shielded, projection).output(111, 0)
+l1.separation(l2, 3.0, transparent, projection).output(120, 0)
+l1.separation(l2, 3.0, shielded, projection).output(121, 0)
 
-deep 
+#deep 
 
 l1 = input(1, 0)
 l2 = input(2, 0)
 
 l1.space(3.0, transparent, projection).output(200, 0)
 l1.space(3.0, shielded, projection).output(201, 0)
+# NOTE: for two-layer checks, the *second* layer
+# shields, but not the first one
 l2.separation(l1, 3.0, transparent, projection).output(210, 0)
 l2.separation(l1, 3.0, shielded, projection).output(211, 0)
+l1.separation(l2, 3.0, transparent, projection).output(220, 0)
+l1.separation(l2, 3.0, shielded, projection).output(221, 0)
 
diff --git a/testdata/drc/drcSimpleTests_au19.gds b/testdata/drc/drcSimpleTests_au19.gds
index 17f23c524..8816a92ff 100644
Binary files a/testdata/drc/drcSimpleTests_au19.gds and b/testdata/drc/drcSimpleTests_au19.gds differ