Tiles should be sorted by the lower number. Tiles should be sorted by the higher number. Play starts going Up . Whether UP or DOWN, the first player of a trick plays a set of dominos containing a played number on one side. The next player must play a set of the exact same size, or pass.
Sets continue to be played until everyone passes, ending the trick.
A player may play multiple times in the same trick. The last person to lay down a set of the given size leads the next trick. This could be five zeroes, but it is played as four. All further sets played in this trick must have a size of four. All players pass after that, ending the trick.