text: var runGame = 0;
  var score = 0;
  
  var gameEndCallback = null;
  
  
  function random(min,max){
   	return Math.round(Math.random() * (max-min) + min);
  }
  
  
  function dropBox(){
    var gameDiv = $(".game");
    var length = random(100, (gameDiv.width() - 100));
    var velocity = random(850, 10000);
    var size = random(50, 150);
    var thisBox = $("<div/>", {
      class: "box",
      style:  "width:" +size+ "px; height:"+size+"px; left:" + length+  "px; transition: transform " +velocity+ "ms linear;"
    });
    
    //set data and bg based on data
    thisBox.data("test", Math.round(Math.random()));
    if(thisBox.data("test")){
      thisBox.css({"background": "url('https://www.festadocovid.com/game/img/ze-povinho.png')", "background-size":"contain"});
    } else {
      thisBox.css({"background": "url('https://www.festadocovid.com/game/img/corona.png')", "background-size":"contain"});
    }
    
    //insert box element
    gameDiv.append(thisBox);
    
    //random start for animation
    setTimeout(function(){
      thisBox.addClass("move");
    }, random(0, 5000) );
    
    //remove this object when animation is over
    thisBox.one("webkitTransitionEnd otransitionend oTransitionEnd msTransitionEnd transitionend",
      function(event) {
      	$(this).remove();
    	});
  }
  
  
  $(document).on('click', '.box', function(){
    
    if($(this).data("test")){
      score += 1;
    } else {
      score -= 1;
    }
    
    $(".score").html(score);
    $(this).remove();
  });
  
  
  function countdown() {
      	var seconds = 30;
  
  	    function tick() {
  	        var counter = document.getElementById("counter");
  
  	        seconds--;
  	        counter.innerHTML = (seconds < 10 ? "0" : "")  + String(seconds) + " S";
  
  	        if( seconds > 0 ) {
  	            setTimeout(tick, 1000);
  	        } else {
  	        	finishGame();
  	        }
  	    }
  
      	tick();
  	}
  
  
  function finishGame(){
  	clearInterval( runGame );
  	runGame = 0;
  
  	alert( score + " Camaradas Infectados\n\nGame over !");
  
  	if( gameEndCallback ){
      	gameEndCallback();
  	}
  }
  
  
  function startGame( endCallback ){
  	gameEndCallback = endCallback;
  	score = 0
  
  	for (i = 0; i < 10; i++) { 
  	  dropBox();
  	}
  
  	runGame =
  		setInterval(
  			function(){
                  for (i = 0; i < 5; i++) { 
                    dropBox();
                  }  
              }, 2500);
  
  	countdown();
  }