A long time ago, i used the same example, provided by YISRAEL.
Manipulated and optimized it and it was working like a charm, without any problems on CHROME (i am always using CHROME).
Maybe you can try it on another COMPUTER.
If something is flickering, maybe even a graphics-card-problem ?
Prove first, that your written project works well or don’t on another PC.
If you get still same results, then → YES <— something is wrong with your code.
COPY your whole code (which is surely inside of an HTML-COMPONENT) —> open ------> JS-FIDDLE or CODE-PEN ----> paste your whole CODE there and run it.
CHECK IF YOU WILL FIND THERE THE SAME BEHAVIOUR!
I would reccomend JS-FIDDLE.