20 into 13 best min fragment found: 5
  Cut up 20 sticks of length 13 like this:
    4 x (32/5 + 33/5)
    4 x (28/5 + 37/5)
    4 x (27/5 + 38/5)
    8 x (5 + 8)
  Reassemble as 13 sticks of length 20 like this:
    4 x (28/5 + 32/5 + 8)
    4 x (27/5 + 33/5 + 8)
    4 x (5 + 37/5 + 38/5)
    1 x (5 + 5 + 5 + 5)