From eloquent javascript + solution

 Create this output:

• "# # # # # # "
• " # # # # # #"
• "# # # # # # "
• " # # # # # #"
• "# # # # # # "
• " # # # # # #"
• "# # # # # # "
• " # # # # # #"
• "# # # # # # "
• " # # # # # #"
• "# # # # # # "
• " # # # # # #"

 Code:

  $(document).ready(function(){
  var l=12;  //l = any
  var chars="# ";
  for(var i=0; i   { var s = "";
     for(var j=0; j       s+=chars[(i%2 + j%2)%2];
      console.log(s);
   }
    });