diff --git a/go/u/try-io.out b/go/u/try-io.out
index 6620c6f5c..f7543d818 100644
--- a/go/u/try-io.out
+++ b/go/u/try-io.out
@@ -335,3 +335,34 @@ pan	pan	1	0.3467901443380824	0.7268028627434533
 eks	pan	2	0.7586799647899636	0.5221511083334797
 wye	wye	3	0.20460330576630303	0.33831852551664776
 eks	wye	4	0.38139939387114097	0.13418874328430463
+
+----------------------------------------------------------------
+mlr --c2j cat u/s.csv
+{
+  "a": "pan",
+  "b": "pan",
+  "i": 1,
+  "x": 0.3467901443380824,
+  "y": 0.7268028627434533
+}
+{
+  "a": "eks",
+  "b": "pan",
+  "i": 2,
+  "x": 0.7586799647899636,
+  "y": 0.5221511083334797
+}
+{
+  "a": "wye",
+  "b": "wye",
+  "i": 3,
+  "x": 0.20460330576630303,
+  "y": 0.33831852551664776
+}
+{
+  "a": "eks",
+  "b": "wye",
+  "i": 4,
+  "x": 0.38139939387114097,
+  "y": 0.13418874328430463
+}