Twelve starts off with sixteen dice, 1 1 1, 2 2 2,  3 3 3 3,  4 4 4, 5 5 5. These pieces are randomly divided between two players.

Players take turns putting one of their unused pieces on an empty position on the board. Each time a player makes a vertical or horizontal row of exactly twelve, the player scores a point.

3, 3, 4, 2 would get a point
5, 4, empty, 3 would get a point

Pennies are used to keep score. The player with the most points wins.
 
 

After some debate about using posterboard with holes in it, coloured popsicle sticks were used to make the board. The goal was to mark positions in a way that preserved the nice blueness of the board. Get a white coloured pencil and a ruler - but do not use tape to mark edges. Ordinary (dollar store) dice were used as pieces, but all those numbers were confusing. Pips can be nicely, permanently removed by scraping them out, but that takes forever. A drill was much faster, but that distorts the dice. The successful solution was using off-brand liquid paper from the dollar store.