diff --git a/src/features/effects/Mask.js b/src/features/effects/Mask.js
index 33b1058..a5edbc0 100644
--- a/src/features/effects/Mask.js
+++ b/src/features/effects/Mask.js
@@ -31,6 +31,10 @@ const options = {
     title: "Invert",
     type: "checkbox",
   },
+  maskBorder: {
+    title: "Draw border",
+    type: "checkbox",
+  }
 }
 
 export default class Mask extends Effect {
@@ -64,6 +68,7 @@ export default class Mask extends Effect {
         maskMinimizeMoves: false,
         maskMachine: "rectangle",
         maskInvert: false,
+        maskBorder: false,
       },
     }
   }
@@ -112,7 +117,7 @@ export default class Mask extends Effect {
         maxRadius: effect.width / 2,
         mask: true,
       })
-      vertices = machine.polish(vertices)
+      vertices = machine.polish(vertices, { border: effect.maskBorder })
     }
 
     return vertices.map((vertex) => {
diff --git a/src/features/machines/Machine.js b/src/features/machines/Machine.js
index a374b67..2f83d76 100644
--- a/src/features/machines/Machine.js
+++ b/src/features/machines/Machine.js
@@ -1,4 +1,4 @@
-import { vertexRoundP, annotateVertices } from "@/common/geometry"
+import { vertexRoundP, annotateVertices, downsample } from "@/common/geometry"
 
 export const machineOptions = {
   name: {
@@ -40,11 +40,13 @@ export default class Machine {
     this.layerInfo = layerInfo
 
     this.enforceLimits().cleanVertices().limitPrecision().optimizePerimeter()
+    if (this.layerInfo.border) this.outlinePerimeter()
     if (this.layerInfo.start) this.addStartPoint()
     if (this.layerInfo.end) this.addEndPoint()
 
     // second call to limit precision for final cleanup
     this.limitPrecision()
+
     return this.vertices
   }
 
diff --git a/src/features/machines/PolarMachine.js b/src/features/machines/PolarMachine.js
index 0c2713b..26e1926 100644
--- a/src/features/machines/PolarMachine.js
+++ b/src/features/machines/PolarMachine.js
@@ -1,4 +1,11 @@
-import { angle, onSegment, arc, annotateVertex } from "@/common/geometry"
+import {
+  angle,
+  onSegment,
+  arc,
+  annotateVertex,
+  subsample,
+  circle,
+} from "@/common/geometry"
 import Victor from "victor"
 import Machine, { machineOptions } from "./Machine"
 
@@ -143,6 +150,17 @@ export default class PolarMachine extends Machine {
     return arc(this.state.maxRadius, start.angle(), end.angle())
   }
 
+  outlinePerimeter() {
+    const last = this.vertices[this.vertices.length - 1]
+
+    if (last) {
+      this.vertices = this.vertices.concat(
+        circle(this.state.maxRadius, parseInt((last.angle() * 64) / Math.PI)),
+      )
+    }
+    return this
+  }
+
   // Returns whether a given path lies on the perimeter of the circle.
   onPerimeter(v1, v2, delta = 1) {
     let rm = Math.pow(this.state.maxRadius, 2)
diff --git a/src/features/machines/RectMachine.js b/src/features/machines/RectMachine.js
index fc149ab..a705437 100644
--- a/src/features/machines/RectMachine.js
+++ b/src/features/machines/RectMachine.js
@@ -137,6 +137,26 @@ export default class RectMachine extends Machine {
     return (rDx < delta && dx < delta) || (rDy < delta && dy < delta)
   }
 
+  outlinePerimeter() {
+    const last = this.vertices[this.vertices.length - 1]
+
+    if (last) {
+      const s = this.nearestPerimeterVertex(last)
+      const idx = this.nearestCornerIndex(s)
+      const corners = [
+        s,
+        cloneVertex(this.corners[idx]),
+        cloneVertex(this.corners[(idx + 1) % 4]),
+        cloneVertex(this.corners[(idx + 2) % 4]),
+        cloneVertex(this.corners[(idx + 3) % 4]),
+        cloneVertex(this.corners[idx]),
+      ]
+      this.vertices = this.vertices.concat(corners)
+    }
+
+    return this
+  }
+
   // Given two perimeter points, traces the shortest valid path between them (stays on
   // perimeter). Returns a list of intermediate points on that path (if any).
   // On further consideration, this could be redone using Dijsktra's algorithm, I believe,