let answer; //answer text

let num; //number to be shown

let isQuestion = true; //program state (question or answer)

​

//numbers to be squared

let minNum = 2;

let maxNum = 16;

let nums = [];

​

function setup() {

  createCanvas(400, 400);

  //populate nums array

  for (let n = minNum; n <= maxNum; n++) {

    nums.push(n);

  }

  //select random number from nums

  num = random(nums);

}

​

function draw() {

  background(229, 255, 234, 125);

  textAlign(CENTER);

  //Display instructions

  textSize(24);

  fill(0, 0, 0);

  text("Randomized Flash Cards:", width / 2, 25);

  text(minNum + "^2 through " + maxNum + "^2", width / 2, 50);

  text("(Click for next question or answer.)", width / 2, 75);

  //Display question

  textSize(48);

  fill(232, 51, 232);

  question = num + "^2 " + " = ?";

  text(question, width / 2, height / 2);

  //If this is not a question card, display answer

  if (!isQuestion) {

    fill(0, 140, 37);

    answer = num ** 2;

    text(answer, width / 2, height / 2 + 50);

  }

}

​

function mouseClicked() {

  //toggle state between question and answer

  isQuestion = !isQuestion;

  //if state updated to a question, generate number for next card

  if (isQuestion) {

     num = random(nums); 

  }

}