A palindrome line contains a sequence of digits which is the same from either direction.
For example, 384676483 or 5885 are valid palindrome lines, but 9696 is not.
An Irregular Sudoku grid with a non-contiguous region is possible, but usually there can be only one, else how to determine to which region the errant cells belong? I’ve kept these connected, albeit tenuously, and the resulting shapes seem like botanical pixel art.
The thing about a mirror is that it doesn’t have much color of its own. So a rainbow mirror needs color to be supplied by you!
If heaven and hell decide that they both are satisfied / Illuminate the NOs on their Vacancy signs // If there’s no one beside you when your soul embarks / Then I’ll follow you into the dark // - with much gratitude to Ben Gibbard
Some people seem fixated on Inuit people having many words for snow, but English does too! From blizzard to whiteout, with flurries, graupel, and drifts, we have so many words. The one this puzzle’s palindrome lines make me think of is sleet.
You need not use SET (Set Equivalence Theory) to solve this one, but it's more fun to do so.