var margin = new Array;
var width  = 216; 
var stop   = 1;
  
function block_action(count){
 if(count>3){
  if(stop == 1)  
  for(var i=1;i<=count;i++){
   var s = document.getElementById("bl"+i);
   if(!margin[i]) margin[i] = 0;
   margin[i] -= 1; s.style.left = margin[i] + "px";
   if(margin[i] < (-width*i) ){
    margin[i] = width*(count-i);
    s.style.left = margin[i];  
   }
  }
  setTimeout("block_action("+count+")",20);  
 }  
}
  
function block_action_stop(){ stop = 1 }
function block_action_play(){ stop = 0 }