diff --git a/benchmarks/3d/periodic_unstructured.geo b/benchmarks/3d/periodic_unstructured.geo
index 316c43595e769a49fef4bdb700143472bfc1062a..7587035410233087f75c990efd6793fca2261ee0 100644
--- a/benchmarks/3d/periodic_unstructured.geo
+++ b/benchmarks/3d/periodic_unstructured.geo
@@ -1,11 +1,11 @@
-Point(1) = {0.2, 0.8, 0,0.006};
+Point(1) = {0.2, 0.8, 0,0.005};
 Point(2) = {0.6, 0.8, 0, 0.05};
 Point(3) = {0.6, 0.6, 0, 0.05};
 Point(4) = {0.5, 0.6, 0, 0.05};
 Point(5) = {0.5, 0.5, 0, 0.05};
 Point(6) = {0.6, 0.5, 0, 0.05};
-Point(7) = {0.6, 0.3, 0, 0.05};
-Point(8) = {0.2, 0.3, 0, 0.05};
+Point(7) = {0.6, 0.3, 0, 0.2};
+Point(8) = {0.2, 0.3, 0, 0.2};
 Line(1) = {2, 1};
 Line(2) = {1, 8};
 Line(3) = {8, 7};
@@ -16,18 +16,16 @@ Line(7) = {4, 3};
 Line(8) = {3, 2};
 Line Loop(9) = {8, 1, 2, 3, 4, 5, 6, 7};
 Plane Surface(10) = {9};
+
+// Nice hack to generate periodic surface meshes on non-extrudable
+// geometries: extrude the surface, then delete all the "middle"
+// entities
+
 Extrude {{0, 1, 0}, {0, 0, 0}, Pi/10} {
   Surface{10}; Layers{1};
 }
-Delete {
-  Surface{27, 23, 51, 47, 43, 31, 35, 39};
-}
 Delete {
   Volume{1};
-}
-Delete {
   Surface{27, 51, 23, 47, 43, 31, 35, 39};
-}
-Delete {
   Line{26, 22, 46, 21, 42, 38, 30, 34};
 }