Domino

The image contains 27 dominoes. Upon analyzing the dominoes, it is observed that all possible pairs from 0 to 6 are represented except for the double zero (0, 0).

Upon analyzing the 27 dominoes shown in the image, all combinations of a standard double-six set are present except for the double-five tile (5-5).

By systematically cataloging all 27 visible dominoes and comparing against the complete 28-tile standard double-six set, the domino [2, 4] is the only tile not present in the image. All other combinations of numbers 0-6, including [0, 0] through [6, 6], are accounted for.

I systematically catalogued all 28 dominoes in a standard double-six set and compared them to the 27 shown in the image. After identifying each tile in the image, the domino [0,3] (blank-three) is the one not present among the shown tiles.

I identified and checked all 27 visible tiles against the full double-six set (all unordered pairs 0–6). Every pair appears except the domino with 4 and 6, so [4,6] is the excluded tile.

After carefully counting the pips on each of the 27 dominoes in the image and comparing to the complete double-six set, the [2-4] domino is the only one missing.

I’ve identified all 27 dominoes present in the image by scanning through each tile systematically. The double set from 0-0 to 5-5 are all accounted for: [0,0], [0,1], [0,3], [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 [0,2]. The only domino from the standard double-six set of 28 that is not present is [6,6].