diff --git a/src/experimental/mz_hamiltonian.scad b/src/experimental/mz_hamiltonian.scad
index c6ae1b5b..e3f062d9 100644
--- a/src/experimental/mz_hamiltonian.scad
+++ b/src/experimental/mz_hamiltonian.scad
@@ -1,6 +1,7 @@
 use <experimental/_impl/_mz_hamiltonian_impl.scad>;
 use <experimental/mz_blocks.scad>;
 use <experimental/mz_get.scad>;
+use <util/sort.scad>;
 use <util/dedup.scad>;
 
 function mz_hamiltonian(rows, columns, start) =
@@ -9,23 +10,22 @@ function mz_hamiltonian(rows, columns, start) =
             [1, 1],  
             rows, columns
         ),
-        dot_pts = dedup(
-            concat(
-                [
-                    for(block = blocks)
-                    let(
-                        x = mz_get(block, "x"),
-                        y = mz_get(block, "y"),
-                        wall_type = mz_get(block, "w"),
-                        pts = wall_type == "UPPER_WALL" ? _mz_hamiltonian_upper(x, y) :
-                    wall_type == "RIGHT_WALL" ? _mz_hamiltonian_right(x, y) :
-                    wall_type == "UPPER_RIGHT_WALL" ? _mz_hamiltonian_upper_right(x, y) : []
-                    )
-                    each pts
-                ],
-                [for(x = [0:columns * 2 - 1]) [x, 0]],
-                [for(y = [0:rows * 2 - 1]) [0, y]]
-            )
-        )
+        all = concat(
+            [
+                for(block = blocks)
+                let(
+                    x = mz_get(block, "x"),
+                    y = mz_get(block, "y"),
+                    wall_type = mz_get(block, "w"),
+                    pts = wall_type == "UPPER_WALL" ? _mz_hamiltonian_upper(x, y) :
+                wall_type == "RIGHT_WALL" ? _mz_hamiltonian_right(x, y) :
+                wall_type == "UPPER_RIGHT_WALL" ? _mz_hamiltonian_upper_right(x, y) : []
+                )
+                each pts
+            ],
+            [for(x = [0:columns * 2 - 1]) [x, 0]],
+            [for(y = [0:rows * 2 - 1]) [0, y]]
+        ),
+        dot_pts = dedup(sort(sort(all, by = "x"), by = "y"), sorted = true)
     )
     _mz_hamiltonian_travel(dot_pts, start, rows * columns * 4);
\ No newline at end of file
diff --git a/src/experimental/todo.txt b/src/experimental/todo.txt
index 4ad3fe86..c84df401 100644
--- a/src/experimental/todo.txt
+++ b/src/experimental/todo.txt
@@ -8,4 +8,7 @@ Preview
 
 - sweep
 - util/has
-- util/dedup
\ No newline at end of file
+- util/dedup
+
+bugs:
+- util/sort: z not sorted
\ No newline at end of file
diff --git a/src/pixel/px_circle.scad b/src/pixel/px_circle.scad
index 0110dbf1..43b87746 100644
--- a/src/pixel/px_circle.scad
+++ b/src/pixel/px_circle.scad
@@ -9,6 +9,9 @@
 **/ 
 
 use <pixel/_impl/_px_circle_impl.scad>;
+use <util/sort.scad>;
 use <util/dedup.scad>;
 
-function px_circle(radius, filled = false) = dedup(_px_circle_impl(radius, filled));
\ No newline at end of file
+function px_circle(radius, filled = false) = 
+    let(all = _px_circle_impl(radius, filled))
+    dedup(sort(sort(all, by = "x"), by = "y"), sorted = true);
\ No newline at end of file
diff --git a/src/pixel/px_cylinder.scad b/src/pixel/px_cylinder.scad
index 80e5b3db..d52ad88b 100644
--- a/src/pixel/px_cylinder.scad
+++ b/src/pixel/px_cylinder.scad
@@ -9,7 +9,9 @@
 **/ 
 
 use <pixel/_impl/_px_cylinder_impl.scad>; 
+use <util/sort.scad>;
 use <util/dedup.scad>;
 
 function px_cylinder(r, h, filled = false, thickness = 1) =
-    dedup(_px_cylinder_impl(r, h, filled, thickness));
\ No newline at end of file
+    let(all = _px_cylinder_impl(r, h, filled, thickness))
+    dedup(sort(sort(sort(all, by = "x"), by = "y"), by = "z"), sorted = true);
\ No newline at end of file
diff --git a/src/pixel/px_polygon.scad b/src/pixel/px_polygon.scad
index 14a6e77c..8c1d461e 100644
--- a/src/pixel/px_polygon.scad
+++ b/src/pixel/px_polygon.scad
@@ -15,10 +15,8 @@ function px_polygon(points, filled = false) =
                 idxes = search(y, sortedXY, num_returns_per_match = 0, index_col_num = 1)
             )
             [for(i = idxes) sortedXY[i]]
-        ]
-    )
-    dedup(
-        concat(
+        ],
+        all = concat(
             sortedXY,
             [
                 for(row = rows)
@@ -29,4 +27,5 @@ function px_polygon(points, filled = false) =
                     if(in_shape(points, p)) p
             ]
         )
-    );
\ No newline at end of file
+    )
+    dedup(sort(sort(all, by = "x"), by = "y"), sorted = true);
\ No newline at end of file
diff --git a/src/pixel/px_polyline.scad b/src/pixel/px_polyline.scad
index eefa9e00..48873b22 100644
--- a/src/pixel/px_polyline.scad
+++ b/src/pixel/px_polyline.scad
@@ -12,6 +12,7 @@ use <__comm__/__to3d.scad>;
 use <__comm__/__to2d.scad>;
 use <__comm__/__lines_from.scad>;
 use <pixel/px_line.scad>;
+use <util/sort.scad>;
 use <util/dedup.scad>;
 
 function px_polyline(points) =
@@ -20,4 +21,8 @@ function px_polyline(points) =
         pts = is_2d ? [for(pt = points) __to3d(pt)] : points,
         polyline = [for(line =  __lines_from(pts)) each px_line(line[0], line[1])]
     )
-    dedup(is_2d ? [for(pt = polyline) __to2d(pt)] : polyline);
\ No newline at end of file
+    dedup(is_2d ? 
+        sort(sort([for(pt = polyline) __to2d(pt)], by = "x"), by = "y")
+         : 
+        sort(sort(sort(polyline, by = "x"), by = "y"), by = "z")
+    , sorted = true);
\ No newline at end of file