diff --git a/src/cairo-bentley-ottmann-rectangular.c b/src/cairo-bentley-ottmann-rectangular.c
index 5541bdc..29f902c 100644
--- a/src/cairo-bentley-ottmann-rectangular.c
+++ b/src/cairo-bentley-ottmann-rectangular.c
@@ -672,10 +672,19 @@ _cairo_bentley_ottmann_tessellate_rectangular_traps (cairo_traps_t *traps,
     cairo_status_t status;
     int i;
 
-    if (unlikely (traps->num_traps <= 1))
+   assert (traps->is_rectangular);
+
+    if (unlikely (traps->num_traps <= 1)) {
+        if (traps->num_traps == 1) {
+            cairo_trapezoid_t *trap = traps->traps;
+            if (trap->left.p1.x > trap->right.p1.x) {
+                cairo_line_t tmp = trap->left;
+                trap->left = trap->right;
+                trap->right = tmp;
+            }
+        }
 	return CAIRO_STATUS_SUCCESS;
-
-    assert (traps->is_rectangular);
+    }
 
     dump_traps (traps, "bo-rects-traps-in.txt");