I was trying to implement OOPs in JS using Functions and written a code to try that out.

Here is the code I tried https://codepen.io/hackhimanshu1024/pen/ZEXErVZ?editors=1111

I created a Function Ball() with desired properties and added helper function of setup, move and moveBall.

I aimed at moving both the balls regularly after an interval.

But the error I encountered is only the second ball is moving, the first ball remains where is was.

Different behavior occurs when only one ball is defined, then that ball moves as it has to be.

I am not able to understand why such behavior is happening.

Pls explain why this is happening. This will help me in understanding JS concepts in much depth.