diff --git a/src/experimental/voronoi2d_cells.scad b/src/experimental/voronoi2d_cells.scad
index fec8d68f..5306b76a 100644
--- a/src/experimental/voronoi2d_cells.scad
+++ b/src/experimental/voronoi2d_cells.scad
@@ -1,5 +1,6 @@
 use <experimental/_impl/_voronoi2d_cells_impl.scad>;
 use <experimental/convex_intersection_for.scad>;
+use <shape_square.scad>;
 
 function voronoi2d_cells(points, region_shape) = 
     let(