Can you arrange a standard set of $28$ dominoes into a rectangle of $7\times8$, where each of the 8 rows sum to $21$ and each of the 7 columns sum to $24$? [![double 6 dominoes][1]][1] <sub>Image from [WikiPedia][2].</sub> Or, alternatively, pack the dominoes into their $7\times4\times2$ box, with equal rows and stacks. [1]: https://i.sstatic.net/sMx5l.png [2]: https://en.wikipedia.org/wiki/Dominoes#Tiles_and_suits