diff --git a/dist/main.cjs.js b/dist/main.cjs.js
index d2b70a2..bb4289e 100644
--- a/dist/main.cjs.js
+++ b/dist/main.cjs.js
@@ -725,6 +725,12 @@ function arcStartSweep(center, start, sweep, counterClockwise) {
         endAngle += 2*Math.PI;
         counterClockwise = true;
     }
+    else if (core.Utils.GT(endAngle, 2*Math.PI)) {
+        endAngle -= 2*Math.PI;
+    }
+    else if (core.Utils.LT(endAngle, -2*Math.PI)) {
+        endAngle += 2*Math.PI;
+    }
     let r = core.vector(center, start).length;
 
     return new core.Arc(center, r, startAngle, endAngle, counterClockwise);
@@ -734,9 +740,16 @@ function arcEndSweep(center, end, sweep, counterClockwise) {
     let endAngle = core.vector(center,end).slope;
     let startAngle = endAngle - sweep;
     if (core.Utils.EQ(startAngle, endAngle)) {
-        endAngle += 2*Math.PI;
+        startAngle += 2*Math.PI;
         counterClockwise = true;
     }
+    else if (core.Utils.GT(startAngle, 2*Math.PI)) {
+        startAngle -= 2*Math.PI;
+    }
+    else if (core.Utils.LT(startAngle, -2*Math.PI)) {
+        startAngle += 2*Math.PI;
+    }
+
     let r = core.vector(center, end).length;
 
     return new core.Arc(center, r, startAngle, endAngle, counterClockwise);
diff --git a/dist/main.esm.js b/dist/main.esm.js
index b9dc350..28abe19 100644
--- a/dist/main.esm.js
+++ b/dist/main.esm.js
@@ -721,6 +721,12 @@ function arcStartSweep(center, start, sweep, counterClockwise) {
         endAngle += 2*Math.PI;
         counterClockwise = true;
     }
+    else if (Utils.GT(endAngle, 2*Math.PI)) {
+        endAngle -= 2*Math.PI;
+    }
+    else if (Utils.LT(endAngle, -2*Math.PI)) {
+        endAngle += 2*Math.PI;
+    }
     let r = vector(center, start).length;
 
     return new Arc(center, r, startAngle, endAngle, counterClockwise);
@@ -730,9 +736,16 @@ function arcEndSweep(center, end, sweep, counterClockwise) {
     let endAngle = vector(center,end).slope;
     let startAngle = endAngle - sweep;
     if (Utils.EQ(startAngle, endAngle)) {
-        endAngle += 2*Math.PI;
+        startAngle += 2*Math.PI;
         counterClockwise = true;
     }
+    else if (Utils.GT(startAngle, 2*Math.PI)) {
+        startAngle -= 2*Math.PI;
+    }
+    else if (Utils.LT(startAngle, -2*Math.PI)) {
+        startAngle += 2*Math.PI;
+    }
+
     let r = vector(center, end).length;
 
     return new Arc(center, r, startAngle, endAngle, counterClockwise);
diff --git a/dist/main.umd.js b/dist/main.umd.js
index 8584f96..7530249 100644
--- a/dist/main.umd.js
+++ b/dist/main.umd.js
@@ -725,6 +725,12 @@
             endAngle += 2*Math.PI;
             counterClockwise = true;
         }
+        else if (core.Utils.GT(endAngle, 2*Math.PI)) {
+            endAngle -= 2*Math.PI;
+        }
+        else if (core.Utils.LT(endAngle, -2*Math.PI)) {
+            endAngle += 2*Math.PI;
+        }
         let r = core.vector(center, start).length;
 
         return new core.Arc(center, r, startAngle, endAngle, counterClockwise);
@@ -734,9 +740,16 @@
         let endAngle = core.vector(center,end).slope;
         let startAngle = endAngle - sweep;
         if (core.Utils.EQ(startAngle, endAngle)) {
-            endAngle += 2*Math.PI;
+            startAngle += 2*Math.PI;
             counterClockwise = true;
         }
+        else if (core.Utils.GT(startAngle, 2*Math.PI)) {
+            startAngle -= 2*Math.PI;
+        }
+        else if (core.Utils.LT(startAngle, -2*Math.PI)) {
+            startAngle += 2*Math.PI;
+        }
+
         let r = core.vector(center, end).length;
 
         return new core.Arc(center, r, startAngle, endAngle, counterClockwise);
diff --git a/package.json b/package.json
index 81e15b5..263d2e9 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@flatten-js/polygon-offset",
-  "version": "1.0.3",
+  "version": "1.0.4",
   "description": "Polygon equidistant offset",
   "main": "dist/main.cjs.js",
   "umd:main": "dist/main.umd.js",
diff --git a/src/createArcs.js b/src/createArcs.js
index a8942bf..77eb631 100644
--- a/src/createArcs.js
+++ b/src/createArcs.js
@@ -19,6 +19,12 @@ export function arcStartSweep(center, start, sweep, counterClockwise) {
         endAngle += 2*Math.PI;
         counterClockwise = true;
     }
+    else if (Utils.GT(endAngle, 2*Math.PI)) {
+        endAngle -= 2*Math.PI;
+    }
+    else if (Utils.LT(endAngle, -2*Math.PI)) {
+        endAngle += 2*Math.PI;
+    }
     let r = vector(center, start).length;
 
     return new Arc(center, r, startAngle, endAngle, counterClockwise);
@@ -28,9 +34,16 @@ export function arcEndSweep(center, end, sweep, counterClockwise) {
     let endAngle = vector(center,end).slope;
     let startAngle = endAngle - sweep;
     if (Utils.EQ(startAngle, endAngle)) {
-        endAngle += 2*Math.PI;
+        startAngle += 2*Math.PI;
         counterClockwise = true;
     }
+    else if (Utils.GT(startAngle, 2*Math.PI)) {
+        startAngle -= 2*Math.PI;
+    }
+    else if (Utils.LT(startAngle, -2*Math.PI)) {
+        startAngle += 2*Math.PI;
+    }
+
     let r = vector(center, end).length;
 
     return new Arc(center, r, startAngle, endAngle, counterClockwise);
diff --git a/src/polygonOffset.js b/src/polygonOffset.js
index 05ed96f..c986923 100644
--- a/src/polygonOffset.js
+++ b/src/polygonOffset.js
@@ -56,7 +56,7 @@ export function offset(polygon, value) {
     return offsetPolygon;
 }
 
-function offsetArc(arc, value) {
+export function offsetArc(arc, value) {
     let edges = [];
 
     let w = Math.abs(value);
@@ -160,7 +160,7 @@ function offsetArc(arc, value) {
     return polygon;
 }
 
-function offsetSegment(seg, value) {
+export function offsetSegment(seg, value) {
     let w = Math.abs(value);
 
     let polygon = new Polygon();
diff --git a/test/test.js b/test/test.js
index bf4297b..74f9d31 100644
--- a/test/test.js
+++ b/test/test.js
@@ -6,6 +6,7 @@ import {point, segment, arc, circle, CW, CCW} from "@flatten-js/core";
 
 import {offset} from "../index.js";
 import {arcSE} from "../src/createArcs";
+import {offsetArc} from "../src/polygonOffset";
 
 describe('#Algorithms.Offset Polygon', function () {
     it('Function offset defined', function () {
@@ -201,4 +202,10 @@ describe('#Algorithms.Offset Polygon', function () {
         expect([...offsetPolygon.faces][0].size).to.be.equal(5);
         expect([...offsetPolygon.faces][1].size).to.be.equal(11);
     });
+
+    it('Method offset arc can create legal polygon. Simple case', function () {
+        let testArc = arc(point(133434061, 124903644), 400000, 0, 4.71238898038469, CW );
+        let testOffsetArc = offsetArc(testArc, 20);
+        expect(testOffsetArc.faces.size).to.be.equal(1);
+    });
 });