Playing cards are a subset of dominoes.

Suppose we take a double-18 set of dominoes and remove all the 0s, 14s, and everything from 1-1 to 13-13 and 15-15 to 18-18. We're left with 1-15 to 13-18 - every domino with a 1 to 13 on one side and a 15 to 18 on the other.

Treat 1-13 as ace to king and 15-18 as the four suits, and voila, playing cards.

It's easier to go and buy this beautiful deck: http://www.bicyclecards.com/products/pl ... omino-deck

Playing cards are also planets:

Take a deck of 52 playing cards, remove 43, make them much bigger and round instead of flat, remove the numbers/suits and spin them round the sun, and voila, planets!

Haha, yes, I have two. But they're only double-9 - not big enough to use for this. Or to use as planets. (Seriously, Kelvin? )