Now look carefully at the character:
Doesn't it look a lot like a baseball diamond? The field on top would be second base; the one to the right, first base; the one to the left, third base; and the mound of "earth" at the bottom would be home plate.
Koreans refer to "first base" as 일루(一壘), "second base" as 이루(二壘), "third base" as 삼루(三壘), and "home plate" as 본루(本壘).
Is this just coincidence? Or were the Chinese playing baseball a thousand years before Columbus discovered America? I wonder.