diff --git a/src/app/util/canvas-util.js b/src/app/util/canvas-util.js
index e5272f19..2a329e8e 100644
--- a/src/app/util/canvas-util.js
+++ b/src/app/util/canvas-util.js
@@ -141,7 +141,7 @@ export const getStartIndex = (lines) => {
   let smallestX1 = lines[0].x1
   let smallestY1 = lines[0].y1
 
-  for (let i = 1; i < arr.length; i++) {
+  for (let i = 1; i < lines.length; i++) {
     if (
       lines[i].x1 < smallestX1 ||
       (lines[i].x1 === smallestX1 && lines[i].y1 < smallestY1)