function addBalls(x,y,num){
 for(var i=0;i<digit[num].length;i++){
  console.log(num + "  " + digit[num].length + " "+ digit[num][i].length);
  for(var j=0;j<digit[num][i].length;j++){
   if(digit[num][i][j] == 1){
    var aBall = {
     x:x+j*2*(RADIUS+1)+(RADIUS+1), //不太理解画横线的地方
     y:y+i*2*(RADIUS+1)+(RADIUS+1),
     g:1.5+Math.random(),
     vx:Math.pow(-1,Math.ceil(Math.random()*1000))*4,
     vy:-5,
     color:colors[Math.floor(Math.random()*colors.length)]
    }
    balls.push(aBall);
   }
  }
 }
}