seconds task   
  4     a b c    
 24     d e f  a group of 3 blank slots occur every 24 seconds
               There are 3 categories of other things. 
               Even if they all land on the same 24 second 
               "window", we can still run one of each
               of them. In other words, each of these 3
               slots could be dedicated as 
               "potential 96, 144 or 600 second thing".
 96     g      run once every 4th group
144     h i j  run one of them every other group 
               (pattern repeats after 6 groups)
600     k      run once every 25th group