Sean @ Make: Online writes:

A Seattle family exposed to the virulent penny floor meme has contracted a more expensive (and therefore probably less contagious) mutant strain that metabolizes nickels instead of pennies. I do like the different color effect this achieves, but by my math (and depending on how much space you leave between the coins) penny flooring costs between $2.50 and $3.00 per square foot, whereas nickel flooring costs four times as much ($10-$12). I did not bother to compute costs for quarter-, dime- (ouch), or Sacagawea dollar-flooring, on the assumption that no one would ever go there. But if they do, please, nobody tell me about it.