Domino

The excluded domino is number 3 and 3

A standard double-six domino set consists of 28 tiles. By counting all the tiles in the image, we identify 27. Inventorying the pairs shows that all double tiles are present (0-0, 1-1, 2-2, 3-3, 4-4, 5-5) except for the double-six tile (6-6).

By systematically cataloging all 27 visible dominoes in the image and comparing against the complete standard double-six domino set (which contains all combinations of numbers 0-6), the domino [2, 3] is missing from the set.

Going through all dominoes in the image systematically, I can identify the following tiles. A standard set has 28 dominoes. After cataloging all visible 27 dominoes, the missing one is [1,4] (1-4).

I inspected the 27 tiles and found every combination from 0–6 except the double six, so the missing domino is 6 and 6.

By systematically identifying all 27 dominoes present in the image and comparing against the full set of 28 double-six dominoes, the missing domino is determined to be [3,4]. The analysis involved identifying all dominoes by their pip counts and positions, accounting for all 0-x combinations (0-0 through 0-6), all doubles (1-1, 2-2, 3-3, 4-4, 5-5, 6-6), and verifying that all other combinations are present except for the 3-4 domino.