How do Variables and Making Images/Drawings Like Fireworks Work?

Question

How do Variables and Making Images/Drawings Like Fireworks Work?

Answer 1

Only need to know sine and cos work.
https://code.sololearn.com/Wi0GQ057lD4N/?ref=app

Answer 2

im not quite sure I understand. Most of the “fireworks” codes on this app/website were created using JavaScript to draw on an HTML canvas