15 into 4 best min fragment found: 13/7
  Cut up 15 sticks of length 4 like this:
    1 x (2 + 2)
    14 x (13/7 + 15/7)
  Reassemble as 4 sticks of length 15 like this:
    2 x (15/7 + 15/7 + 15/7 + 15/7 + 15/7 + 15/7 + 15/7)
    2 x (13/7 + 13/7 + 13/7 + 13/7 + 13/7 + 13/7 + 13/7 + 2)