I realized recently that the number eight is the only number that people will preceed with the word "figure".

People will say "how do you figure?" in reference to math, and they'll say "I need to see those figures" in references to numbers in general, but not a specific number. You never hear a teacher ask "Timmy, is that a figure 5 or a figure 6"? You never hear two guys saying "Hey Bob, let's do figure 3s in this car." "We can't Lou, the road is too narrow; we'll only be able to do figure 1s." However, you may hear "That's so weird: that cloud looks like a figure 8."

Go figure.