commit fd4beb03f1f741c07f3283bbf06ac5c5ada8ee54
Author: cx <908666218@qq.com>
Date:   Thu Sep 24 16:08:01 2020 +0800

diff --git a/Demo.md b/Demo.md
new file mode 100644
index 0000000..57055a6
--- /dev/null
+++ b/Demo.md
@@ -0,0 +1,12 @@
+```
+
+import { Polyline } from "webcad-api";
+import { Vector3 } from "three";
+let polyline = new Polyline();
+polyline.RectangleFrom2Pt(new Vector3(0, 0, 0), new Vector3(100, 100, 0));
+console.log(polyline);
+
+console.log(polyline.Area);
+console.log(polyline.GetOffsetCurves(3));
+```
+