it’s possible to arrange all the dominoes in a cycle respecting the usual rules of the game using graph theory. u can represent each domino as a vertex in the graph, where each vertex has two edges connecting it to other vertices. By connecting the vertices in such a way that the edges match the numbers on the dominoes, create a cycle that includes all the dominoes. the cycle is known as an ‘Eulerian cycle’ it proves that it is possible to arrange all the dominoes in a cycle respecting the usual rules of the game.