"I will leave her just sitting," he said.
Another cat approached - Max, who has issues with Nora - and when the composer stroked him, that is when Nora decided she would perform.
She hunched forward and extended her right front paw over the keyboard.
She tapped four notes.
Then she settled back down on the bench, stretching her generous gray tabby frame. Enough playing.
Betsy Alexander and her husband Burnell Yow! are members of Philadelphia Dumpster Divers, artists who do wondrous things with discarded objects. Nora is their most notorious find.
They came upon the stray from the Camden streets at a Cherry Hill shelter in 2004. From the beginning, Nora did not mix with the other felines at the couple's Naudain Street home.
One night in 2005 they were upstairs when they heard sounds coming from the music room where Alexander teaches piano students.
Says Alexander: "It was the same note over and over, not the sound of a cat walking across the keys, which happens." Thinking they might have an intruder, they rushed downstairs only to find Nora sitting at the keyboard. She looked at them, then returned to playing.
The cat leaped from novelty to celebrity in 2007 when Yow! posted a two-minute-45-second video on YouTube of Nora's atonal hammerings.
By the end of the first day 71 people had somehow found the video.
That was more than 32 million hits ago. Today Nora is Philadelphia's most famous cat, with two books to her name, T-shirts, bumper stickers, a website, blog, Facebook page and Twitter account, calenders and a journal. Alexander and Yow!, who have worked for decades to find audiences for their art, describe themselves as the animal's personal assistants.
While many felines have won Internet fame - LOLcats, Boozecats, and Bonsai Kitten, as well as Maru, who climbs into boxes; Lenin, who resembles the Soviet leader; or Tulle, who is famous for being fat - no other has inspired a serious piece of music.
A friend sent Piecaitis a copy of Nora's initial video in Lithuania, where he conducts the Klaipeda Chamber Orchestra.
"I was so amazed," said the 43-year-old maestro, who now lives in Karlsruhe, Germany. "It had such feeling, such Stimmung."
His first thought: Children would love the video.
"I kept listening to it over and over," he said. He had a composer friend in mind who might want to use some of Nora's playing in a longer piece of orchestral music. Piecaitis wrote to the Philadelphia couple, explaining his intentions, and they sent him all the video of Nora they had.
But Piecaitis couldn't let go. He had never composed his own music, although he always wanted to. He began rearranging Nora's notes, which he'd transcribed over six pages, then added instruments: more piano, clarinet, flute, vibraphone and triangle.
He built a four-minute piece around Nora's playing. In June 2009, he conducted its debut in Klaipeda, with the musicians seated in front of a giant video of Nora at her keyboard.
More than 20 performances have followed - in the Netherlands, England, Canada, and the United States, where Richard Rosenberg has conducted CATcerto four times, most recently in June at the National Music Festival in Chestertown, Md.
"The piece sounds like it could be a joke, and maybe some aspect is," said Rosenberg, former conductor of the Pennsylvania Ballet. "But the fact is, the tunes that were composed by the cat are really quite beautiful and quite rich in what they allowed Mindaugas Piecaitis to expound upon. He wrote a piece that's four minutes long that works as well as something by Rachmaninoff or Brubeck."
Accompanying Nora is demanding, Rosenberg said, because the musicians must play to her recording, which is unyielding. "In many ways," he said, "it's like playing with a human soloist, in the way the soloist pretty much ignores the conductor."
To view a video of the maestro and the piano-playing cat, go to: www.philly.com/catcerto
Contact Daniel Rubin at firstname.lastname@example.org, 215-854-5917, on Twitter @danielrubin or on Facebook at http://ph.ly/DanRubin