​

function setup() {

  createCanvas(600, 600);

  background(0);

  drawColor = color('#5D8DF5');

}

​

function draw() {

  if (key === 'a') {

    drawColor = color('#7753FA');

  } else if (key === 'b') {

    drawColor = color('#5D8DF5');

  }

  stroke(drawColor);

  if(mouseIsPressed) {

    line(width/2, height/2, mouseX, mouseY);

  }

}