2A Functions

let j = 1 

let k = 1

let maxOpacity = 50

let maxRadius = 25 

​

function setup(){

  createCanvas(windowWidth, windowHeight) 

  background(255) 

  noStroke()

​

}

​

​

function draw(){

  // fill(0)

  // ellipse(mouseX,mouseY,5,5)

​

  pen(mouseX,mouseY,j,k)

  j+= 10

  k+= 0.1

  if (j > maxRadius){

    j = 1 

    maxRadius = random(5,100)

  }

  if (k > maxOpacity){

    k = 1

  }

}

​

function pen(x,y,r,a){

  fill(0,a)

  ellipse(mouseX,mouseY,r,r)

}

​

function mousePressed(){

  background(255)

}