diff --git a/src/triangle/_impl/_tri_delaunay_voronoi_impl.scad b/src/triangle/_impl/_tri_delaunay_voronoi_impl.scad
index 9b91bb91..9f392a71 100644
--- a/src/triangle/_impl/_tri_delaunay_voronoi_impl.scad
+++ b/src/triangle/_impl/_tri_delaunay_voronoi_impl.scad
@@ -2,18 +2,18 @@ use <../tri_delaunay.scad>;
 use <../../util/map/hashmap_get.scad>;
 use <../../util/find_index.scad>;
 
-function indicesOfCell(iTris, triIndices) = 
+function indicesOfCell(iTris, triIndices, indicesOfCell) = 
     let(
 	    vi = iTris[0][0],
 		indices = [],
 		leng = len(iTris)
 	)
-	_indicesOfCell(iTris, triIndices, leng, indices, vi);
+	_indicesOfCell(iTris, triIndices, leng, indices, vi, indicesOfCell);
 
-function _indicesOfCell(iTris, triIndices, leng, indices, vi, i = 0) =
+function _indicesOfCell(iTris, triIndices, leng, indices, vi, indicesOfCell, i = 0) =
     i == leng ? indices :
 	let(
 	    t = iTris[find_index(iTris, function(t) t[0] == vi)],
-		nIndices = concat(indices, hashmap_get(triIndices, t))
+		nIndices = concat(indices, hashmap_get(triIndices, t, hash = indicesOfCell))
 	)
-	_indicesOfCell(iTris, triIndices, leng, nIndices, t[1], i + 1);
+	_indicesOfCell(iTris, triIndices, leng, nIndices, t[1], indicesOfCell, i + 1);
diff --git a/src/triangle/tri_delaunay_voronoi.scad b/src/triangle/tri_delaunay_voronoi.scad
index ec897436..7e75845b 100644
--- a/src/triangle/tri_delaunay_voronoi.scad
+++ b/src/triangle/tri_delaunay_voronoi.scad
@@ -7,12 +7,13 @@ use <../util/reverse.scad>;
 
 function tri_delaunay_voronoi(d) = 
     let(
+		_indices_hash = function(indices) indices[0] * 961 + indices[1] * 31 + indices[2],
 	    coords = delaunay_coords(d),
 		coords_leng = len(coords),
 		circles = delaunay_circles(d),
 		tris = hashmap_keys(delaunay_triangles(d)),
         // circumcircle centers
-        vertices = [for(t = tris) hashmap_get(circles, t)[0]],
+        vertices = [for(t = tris) hashmap_get(circles, t, hash = _indices_hash)[0]],
 		i_rts = [
 			for(i = [0:len(tris) - 1])
 			let(
@@ -40,10 +41,10 @@ function tri_delaunay_voronoi(d) =
 			    rt3 = [a, b, c]
 			) 
 			each [[rt1, i], [rt2, i], [rt3, i]]
-		]),
+		], hash = _indices_hash),
 		cells = [
 		    for(i = [4:coords_leng - 1])
-			reverse(indicesOfCell(connectedTris[i], triIndices)) // counter-clockwise
+			reverse(indicesOfCell(connectedTris[i], triIndices, _indices_hash)) // counter-clockwise
 		]
     )
 	[for(cell = cells) [for(i = cell) vertices[i]]];