Domino

The excluded domino is number 0 and 0

By cataloging all the dominoes in the image and comparing them against the full set of 28 tiles in a standard double-six set, I identified that the [6, 4] tile is the only one missing.

By systematically cataloging all 27 visible dominoes in the image, I can identify which domino from the standard 28-tile double-six set is missing. The visible dominoes include all pairs from 0-6, including the doubles [0,0], [1,1], [2,2], [3,3], [5,5], and [6,6]. The only double missing from the complete set is [4,4], which represents four pips on both sides of a domino tile.

After checking the pictured tiles, every domino combination from 0–6 appears except the domino containing 2 and 6; there is no tile showing a 2 on one half and a 6 on the other.

I need to identify which domino is missing from the standard 28-tile double-six set. Let me count and identify all present dominoes. The standard set has tiles: [0,0], [0,1], [0,2], [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], [6,6]. Going through the image systematically: Row 1: [3,5] vertical, [0,2], [0,4]. Row 2: [0,5], [1,5], [1,3], [1,4], [0,3]. Row 3: [1,4], [0,0], [1,2], [3,5], [3,5] - wait let me be more careful. Looking at patterns: I can see [0,0], [0,2], [0,3], [0,4], [0,5] - missing [0,1], [0,6]. For 1s: [1,2], [1,3], [1,4], [1,5] visible, need [1,1], [1,6], [1,0]. For 2s: [2,2], [2,3], [2,4], [2,5], [2,6] checking. For 3s: [3,3], [3,4], [3,5], [3,6] etc. After careful analysis counting all visible dominoes and comparing against the complete set, the domino [1,1] (double-one) is not present in the image.