For a minute or two she stood looking at the
house, and wondering what to do next, when
suddenly a footman in livery came running out of
the wood—(she considered him to be a footman
because he was in livery: otherwise, judging by
his face only, she would have called him a fish)—
and rapped loudly at the door with his knuckles.
It was opened by another footman in livery, with
a round face, and large eyes like a frog; and
both footmen, Alice noticed, had powdered hair
that curled all over their heads.
Identify the simile used in the passage.