diff --git a/vpsdk/fonttools/fonttools.vp b/vpsdk/fonttools/fonttools.vp
index 3009083..eb0fd74 100644
--- a/vpsdk/fonttools/fonttools.vp
+++ b/vpsdk/fonttools/fonttools.vp
@@ -240,6 +240,7 @@ def _build_contour(start: int, end: int):
                 cx = _px[nn]
                 cy = _py[nn]
                 cur = nn
+                if nn == first_on: break
             else:
                 mx: float = (_px[ctrl] + _px[nn]) / 2.0
                 my: float = (_py[ctrl] + _py[nn]) / 2.0