function(a,b,c) {
  setInterval(function() {
    c=-~c; // incremented on each invocation 
    for(
      b=0; // the segment index
      b<8; // 8 segments (dots)
      c-1||(a.innerHTML+='<b>•'), // create markup upon the first call 
      a.childNodes[b].className='b'+b+' o'+(c+b++)%8 // assign two classes: b<#> and o<#>
    );
  },100) // invoke every 100ms
}