diff --git a/latex/ystikz.sty b/latex/ystikz.sty
index 144fafc..d7498dd 100644
--- a/latex/ystikz.sty
+++ b/latex/ystikz.sty
@@ -70,7 +70,8 @@
     }
   },
   ssarbre/.style={isosceles triangle, draw, shape border rotate=90, minimum size=.7cm, child anchor=apex, anchor=apex},
-  square/.style={regular polygon,regular polygon sides=4, inner sep=0pt, minimum size=.7cm}
+  square/.style={regular polygon,regular polygon sides=4, inner sep=0pt, minimum size=.7cm},
+  susp/.style={draw=none, no edge},
 }
 
 \tikzstyle{basevertex} = [circle,