Domino

After listing all 28 tiles in a standard double-six set and comparing them to the tiles present in the image, the [0, 4] tile (blank and four) is the only one missing.

By systematically checking all 28 possible dominoes in a standard double-six set, I identified all visible tiles in the image. Counting the dots on each domino, I found dominoes representing all pairs from [0,0] through [6,6], with one exception: [1,1] is the only domino missing from the complete set of 28 tiles.

The image contains 27 domino tiles. A standard double-six domino set has 28 tiles, representing every possible pair of numbers from 0 to 6. By examining the image, we can identify the missing tile by checking for the absence of a specific combination. Upon inspection, it’s clear that the double-blank tile (0, 0) is missing.

All other domino pairs and doubles are present in the image, but the double-six tile (6-6) is not visible, so the excluded domino is 6 and 6.

Analyzing the 27 dominoes present: Row 1 contains [1,3], [0,2], [2,3], [0,3], [1,2], [1,4]. Row 2 contains [1,5], [4,5], [2,4], [0,4], [5,5], [2,2]. Row 3 contains [2,5], [4,6]. Row 4 contains [3,4], [4,4], [0,5], [0,0]. Row 5 contains [3,5], [0,1], [1,1], [2,6], [3,6]. Row 6 contains [3,3], [5,6]. The complete set requires 28 dominoes. All dominoes from [0,0] through [5,6] are accounted for except [0,6], and [6,6] is also missing from the count. Checking the domino at row 4, column 5 reveals it is [0,5] (blank top, 5 dots bottom), not [0,6]. Therefore, the missing domino is [0,6].