Logic Masters Deutschland e.V.

The little brother of Eternal Recurrence. The initial idea was to have a playable 6x6 example to accompany it, but it was so hard to set that I had given up. After encouragements from bodemeister and earthpuzzles however, I gave it another shot, and now there it is! And so not only it is offered to you here, but it comes with its own practice puzzle under the form of a Dynamic Fog 6x6, as well as illustrations of the mechanics further below.

The provisional difficulty is set for solvers new to the ruleset, and the hope is that the practice puzzle will help bring it down noticeably. And finally, for those who would like to keep exploring this ruleset, here is a link to all the other Still Life puzzles.




RULES

Normal 6x6 sudoku rules apply: Place the digits 1 to 6 in each row, column, and 2x3 box.

STILL LIFE
Shade some cells green ("active cells") such that the – up to – eight cells neighboring each green cell contain exactly 2 or 3 other green cells and the neighbors of each 'unshaded' – or black/red/etc. – cell ("inactive cells") do not contain exactly 3 green cells.
– A CIRCLED cell's digit indicates the number of cells that are in the SAME state as its own in its neighborhood, including its own cell
– A SQUARED cell's digit indicates the number of cells that are in a DIFFERENT state from its own in its neighborhood (therefore not including its own cell)

PALINDROMES
– All lines in the grid are Palindromes, where the order of digits along a line reads the same forwards and backwards (eg, 1-3-6-3-1).
– Every digit on a Palindrome Line must either be a valid CIRCLED cell or a valid SQUARED cell, or both at once, per the Still Life rules.

Play the puzzle on Sudokupad

In Example 1, a 3x3 box with a Game of Life pattern is shown (green for Alive cells, grey for Dead cells). But the cells marked with a ! are unstable : they either are dead but with 3 alive neighbors, or alive but with less than 2 or more than 3 alive neighbors. Therefore this pattern is not a Still Life pattern, and can not appear in a Still Life Sudoku puzzle.

In Example 2 (using the digits of a normal 9x9 sudoku grid), a 3x3 box is shown filled with digits and clues (circles and squares), the Game of Life pattern that is shown is stable, and all the clues are fulfilled. This could appear in a Still Life Sudoku puzzle.