By Tom Lane
BBC News, New York
Ms Ono will auction off the pieces to raise money for charity
If you have ever wanted a piece of art by Yoko Ono, now is your chance.
The Japanese artist and widow of John Lennon unveiled a new work on the occasion of the United Nation's World Autism Awareness Day.
Her seven-foot (2.1m) mural, entitled "Promise", currently stands in the lobby at the UN in New York, but will be auctioned for an autism charity.
The installation depicts fluffy white clouds against a clear blue sky and is made up of 67 jigsaw-like pieces.
These will be broken down, signed by the artist and auctioned off. The money raised will go to the charity Autism Speaks.
The unveiled work is already missing two pieces. Ms Ono hopes that all 67 pieces will be reunited once a cure for autism is discovered.
Speaking in front of a crowd at the unveiling, she said, "Once the solution for autism is discovered, we will see the sky shimmering in its original beauty, with no holes."
Experts estimate that between 35 million and 67 million people worldwide suffer from autism.
The Chilean ambassador to the UN, Heraldo Munoz, told reporters, "Oftentimes [autism] is thought to be a disease of developed countries. It is not."
He said that this year more children would be diagnosed with autism than cancer, diabetes, Down's Syndrome and Aids.
Autism Speaks said this UN event was one of 100 others that took place around the world, including theatre productions, rallies and fundraisers.
Sarah Brown, the wife of British Prime Minister Gordon Brown, also released a public service announcement on the subject.