Editing No free lunch theorem (section)

==Example==
Posit a toy universe that exists for exactly two days and on each day contains exactly one object: a square or a triangle. The universe has exactly four possible histories:
# (square, triangle): the universe contains a square on day 1, and a triangle on day 2
# (square, square)
# (triangle, triangle)
# (triangle, square)

Any prediction strategy that succeeds for history #2, by predicting a square on day 2 if there is a square on day 1, will fail on history #1, and vice versa. If all histories are equally likely, then any prediction strategy will score the same, with the same accuracy rate of 0.5.<ref>{{Cite journal |last=Forster |first=Malcolm R. |date=1999 |journal=Minds and Machines |volume=9 |issue=4 | title=How do Simple Rules 'Fit to Reality' in a Complex World? |pages=543–564 |doi=10.1023/A:1008304819398 |s2cid=8802657}}</ref>