Mirror, Art, or useless?

Hmm, what a question. But we must also answer what science and sport are.
" Science is a first-rate piece of furniture for a man's upper chamber, if he has common sense on the ground floor. " - Holmes
"Sports is the very fiber of all we stand for. It keeps our spirits alive." - FDR
So chess is a useless hammer, a piece of furniture, or a fibery mirror...

Chess is everything - art, science, and sport. - Karpov
Art is not a mirror of life, but a hammer with which to shape it. - Gorky
All art is quite useless - Wilde
So is chess a mirror, a hammer, or useless?
This thread should be called "mirror, hammer or useless?" (DOH!
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