The description calls
shuffle() twice. The first time, it says
Shuffle the array [1,2,3] and return its result, and the second time, it says
Returns the random shuffling of array [1,2,3].
I thought this meant that it should shuffle the array only once and cache that result, and all subsequent calls to
shuffle() would return that cached shuffled array. Turns out you're supposed to reshuffle each time.