Solution:
We may also count duplicates by doing casework on buttons lit:
- 1 button lit: There are 6 arrangements but all are the same, so we need to subtract 5 duplicates in this case.
- 2 buttons lit: There are 4 indistinguishable ways for the buttons to be vertically adjacent, 3 to be horizontally adjacent, 2 ways for the buttons to be diagonally adjacent for each of 2 directions of diagonals, and 2 for when the lights are in the same vertical line but not adjacent. Since we need to count each of these cases only once, the number of duplicates we need to subtract is 3 (2 vertically adjacent), 2 (2 horizontally adjacent), 2×1 (2 diagonally adjacent), and 1 (2 in same vertical line but not adjacent) for a total of 8 duplicates.
- 3 buttons lit: There are 2 indistinguishable ways for all the buttons in a column to be lit and 2 ways for the buttons to be lit in the shape of an L, given the rotation of the L. Thus, the number of duplicates we need to subtract is 1 (1 column), 1×4 (rotations of L), for a total of 5 duplicates.
- 4 buttons lit: There are 2 indistinguishable ways for the lights to be arranged in a square (and no other duplicates), so we need to subtract 1 duplicate in this case.
- When there are 5 or 6 buttons lit, all of the arrangements of lights are distinct, so we do not subtract any duplicates for these cases.
Thus, the total number of arrangements is 64−(1+5+8+5+1)=44.