diff --git a/phonetics-feature-tree.scm b/phonetics-feature-tree.scm
index 3f83089..bb8c211 100644
--- a/phonetics-feature-tree.scm
+++ b/phonetics-feature-tree.scm
@@ -112,4 +112,15 @@
        ("[cor]" () ())
        ("{cor}" () ()))))))
 
-(display (to-dot cons-tree)) (newline)
+(define verbs
+  '("[verbs]"
+    ("[réel]"
+     ("[passé]" () ())
+     ("{passé}" () ()))
+    ("{réel}"
+     ("[optatif]" () ())
+     ("{optatif}"
+      ("[passé]" () ())
+      ("{passé}" () ())))))
+
+(display (to-dot verbs)) (newline)