Kidney Shaped

I was browsing craigslist recently and noticed an ad for a “Kidney Shaped” table, and it started me thinking.

Kidney Shaped
Of all the organs in the body, why is the Kidney the only one associated (besides the heart – which doesn’t count since a heart isn’t actually heart shaped) with a particular shape? To my knowledge no other internal organs purposely get furniture (or anything else) made in their image.

Wife: Honey, look at this great spleen shaped table I just found.
Husband: Awesome! That is going to look so good next to our liver shaped couch and brain shaped ottoman!