# Fill in the blank to win

Given the six, four digit numbers below, find me a seventh that matches the pattern.

2058
1724
1234
6245
5683
8756
????


Note that there are many possible answers, but if you find the pattern, it should be absolutely obvious if it's correct or not.

• I'm guessing this is a variation of my puzzle? :P – Joe Z. Mar 28 '15 at 6:15
• @Joe - it was trying to solve yours that made me think of this one. :) ...No idea how close their solutions are though, as I couldn't crack yours. – Alconja Mar 28 '15 at 6:22
• By "many possible answers", do you mean "many correct answers"? – Joe Z. Mar 28 '15 at 6:26
• Having seen JoeZ's solution and then looked again at the first 2 rows of his puzzle, I see how you came up with this! ;-) @JoeZ. I think your puzzle will inspire a lot of new ones as people come up with increasingly crazy ideas that don't actually work with yours. – Rand al'Thor Mar 28 '15 at 19:59
• @randal'thor If that happens, that's a great thing for this community! I look forward to solving all of them. :P – Joe Z. Mar 28 '15 at 20:01

Consider the number pad on a phone:

1 2 3
4 5 6
7 8 9
* 0 #


Now, consider the positions that each of the numbers fills.

. 2 .   1 2 .   1 2 3   . 2 .   . . 3   . . .
. 5 .   4 . .   4 . .   4 5 6   . 5 6   . 5 6
. 8 .   7 . .   . . .   . . .   . 8 .   7 8 .
0       .       .       .       .       .


These are six of the seven pieces that appears in Tetris. The last remaining piece is the square, which can appear in four different positions:

1 2 .   . . .   . 2 3   . . .
4 5 .   4 5 .   . 5 6   . 5 6
. . .   7 8 .   . . .   . 8 9
.       .       .       .


So any permutation of 1245, 2356, 4578, or 5689 would be a correct answer.

• Well done. Definitely one of the possible correct answers. :) – Alconja Mar 28 '15 at 7:07
• That was actually an interesting, frustrating puzzle. I loved the more-than-one-correct-answer twist, which actually made it harder to think about, if you can believe it. – Joe Z. Mar 28 '15 at 7:20