function setup() {
  createCanvas(windowWidth, windowHeight);
  background(255);
  cursor(CROSS);
  strokeWeight(1);

  c = color(181, 157, 0);
}
draw tool. draw with a rotating line.

MOUSE
drag                : draw

KEYS
1-4                 : switch default colors
delete/backspace    : clear screen
d                   : reverse direction and mirrow angle
space               : new random color
arrow left          : rotaion speed -
arrow right         : rotaion speed +
arrow up            : line length +
arrow down          : line length -
s                   : save png