Domino

The excluded domino is number 3 and 3

By systematically checking a standard double-six set against the image, the domino with values 0 (blank) and 3 is missing. The other 27 tiles (0-0, 0-1, 0-2, 0-4, 0-5, 0-6, 1-1, 1-2, 1-3, 1-4, 1-5, 1-6, 2-2, 2-3, 2-4, 2-5, 2-6, 3-3, 3-4, 3-5, 3-6, 4-4, 4-5, 4-6, 5-5, 5-6, and 6-6) are all present.

By systematically examining all 27 dominoes in the image and cross-referencing against the complete set of 28 unique domino tiles (all combinations of numbers 0-6), the domino [4, 4] (double-four) is the only tile not present in the collection shown.

I systematically catalogued all visible dominoes in the image and compared them against the complete set of 28 dominoes (all combinations from 0-0 to 6-6). After checking each domino visible in the image, the combination [0,3] (blank/three) is the one not present among the 27 shown dominoes.

Scanning the image shows all domino combinations except the double six tile; there is no domino with six pips on both ends (6|6) present among the 27 shown.

The image contains 27 dominoes. By systematically identifying all dominoes in the 0-x series: [0,0] (vertical double-blank), [0,1] (horizontal), [0,2] (horizontal top-right), [0,3] (vertical), [0,4] (vertical next to [0,3]), and [0,5] (horizontal), all are present except [0,6]. The domino [0,6] is the only missing tile from the complete double-six set.