keyIsPressed is a built-in Boolean variable. 

​

Boolean means only reports the values true or false. 

*/

​

function setup() {

  createCanvas(400, 400)

}

​

function draw() {

  background(220)

  fill(255)//white

  //change fill if any key is pressed

  if (keyIsPressed && key == "d") {

    fill(0)//black

  } 

  rect(25, 25, 50, 50)

​

  //check out the value of the keyIsPressed variable in the console

  //console.log(key)

  console.log(key)

}//end draw