17.09.2019, 11:57
To shed some light on this interesting history...
The puzzle first appeared in a GP Instruction Booklet here: https://gp.worldpuzzle.org/content/instr...-booklet-5 - this is a round authored by Fred, and he credits himself in the instructions.
The next GP round to feature a Palindrome Sudoku is this one: https://gp.worldpuzzle.org/content/instr...booklet-14 - this IB uses the same palindrome example. The IB contains the following sentence: "Examples in this instruction booklet are mostly from prior Sudoku Grand Prix Instruction booklets. We thank the original authors for these examples."
At that point, the credit to Fred is lost, and, I presume, the puzzle assumed fair game for future IBs. The next Palindrome Sudoku appears in 2016 Round 1, and indeed the same example is used.
The puzzle first appeared in a GP Instruction Booklet here: https://gp.worldpuzzle.org/content/instr...-booklet-5 - this is a round authored by Fred, and he credits himself in the instructions.
The next GP round to feature a Palindrome Sudoku is this one: https://gp.worldpuzzle.org/content/instr...booklet-14 - this IB uses the same palindrome example. The IB contains the following sentence: "Examples in this instruction booklet are mostly from prior Sudoku Grand Prix Instruction booklets. We thank the original authors for these examples."
At that point, the credit to Fred is lost, and, I presume, the puzzle assumed fair game for future IBs. The next Palindrome Sudoku appears in 2016 Round 1, and indeed the same example is used.