The Symmetric Icon Attractor is defined by a set of equations as
defined on this web page:
https://softologyblog.wordpress.com/2017/03/04/2d-strange-attractors/
Change the values of the parameters a, b, c, and d by using the sliders.
Key 'r': Redraw with a random set of parameters.
LEFT_ARROW: Draw with few points (faster).
RIGHT_ARROW: Draw with many more points (slower).
Key 'e': Save a high-resolution PNG of the current image.
Key 'a': Increment the number of points.
Key 's': Decrement the number of points.
This p5js code is scrollable.