text: let canvas = document.getElementById("snake");
  let context = canvas.getContext("2d");
  let box = 32;
  let snake = [];
  snake[0] ={
      x: 8 * box,
      y: 8 * box
  }
  let direction = "right";
  let food ={
      x: Math.floor(Math.random() * 15 + 1) * box,
      y: Math.floor(Math.random() * 15 + 1) * box
  }
  
  function criarBG(){
      context.fillStyle = "lightgreen";
      context.fillRect(0, 0, 16*box, 16*box);
  }
  
  function criarCobrinha (){
      for(i = 0; i < snake.length; i++){
          context.fillStyle = "green";
          context.fillRect(snake[i].x, snake[i].y, box, box);
      }
  }
  
  function drawFood (){
      context.fillStyle = "red";
      context.fillRect(food.x, food.y, box, box);
  }
  
  document.addEventListener('keydown', update);
  
  function update(event){
      if(event.keyCode == 37 && direction != 'right') direction = 'left';
      if(event.keyCode == 38 && direction != 'down') direction = 'up';
      if(event.keyCode == 39 && direction != 'left') direction = 'right';
      if(event.keyCode == 40 && direction != 'up') direction = 'down';
  }
  
  function iniciarJogo(){    
  
      if(snake[0].x > 15*box && direction == "right") snake[0].x = 0;
      if(snake[0].x < 0 && direction == 'left') snake[0].x = 16 * box;
      if(snake[0].y > 15*box && direction == "down") snake[0].y = 0;
      if(snake[0].y < 0 && direction == 'up') snake[0].y = 16 * box;
      
      for(i = 1; i < snake.length; i++){
          if(snake[0].x == snake[i].x && snake[0].y == snake[i].y){
              clearInterval(jogo);
              alert('Game Over :(');
          }
      }
  
      criarBG();
      criarCobrinha();
      drawFood();
  
      let snakeX = snake[0].x;
      let snakeY = snake[0].y;
  
      if(direction == "right") snakeX += box;
      if(direction == "left") snakeX -= box;
      if (direction == "up") snakeY -= box;
      if(direction == "down") snakeY += box;
  
      if(snakeX != food.x || snakeY != food.y){
          snake.pop();
      }else{
          food.x = Math.floor(Math.random() * 15 +1) * box;
          food.y = Math.floor(Math.random() * 15 +1) * box;
      }
      
      let newHead ={
          x: snakeX,
          y: snakeY
      }
  
      snake.unshift(newHead);
  }
  
  let jogo = setInterval(iniciarJogo, 100);