diff --git a/src/interpolation/helpers.js b/src/interpolation/helpers.js
index 8d8ae81..92c6614 100644
--- a/src/interpolation/helpers.js
+++ b/src/interpolation/helpers.js
@@ -24,7 +24,7 @@ export function takeSampleFrom(sourceList, amount) {
     }
     randElements.push(rand);
   }
-  var remainder = sourceList.filter(function (obj) {
+  let remainder = sourceList.filter(function (obj) {
     return !randElements.includes(obj);
   });
 
@@ -36,20 +36,17 @@ export function takeSampleFrom(sourceList, amount) {
 
 /**
  * With a circle radius r, and center at (h,k),
- * Find the coordinate of a point at angle degrees
+ * Find the coordinate of on the circle with the specified angle degrees
  * @param {number} h
  * @param {number} k
- * @param {number} angle
+ * @param {number} angle (degree)
  * @param {number} r
  * @return {object} - coordinate {x: number, y: number} of the point
  */
 export function pointOnCircle(h, k, angle, r) {
-  let x = h + r*Math.cos(toRadians(angle));
-  let y = k + r*Math.sin(toRadians(angle));
-
   return {
-    x: x,
-    y: y
+    x: h + r*Math.cos(toRadians(angle)),
+    y: k + r*Math.sin(toRadians(angle))
   };
 }