His survival skills are sharp after years on the streets, but he moves warily at times, and feels for the sawed-off wooden chair leg attached to his belt and hidden under a sweater tied around his waist. He remembers how that man looked after the horrible beating. Maybe it was a drug deal, he says, or a hustle gone bad.
I ask Nathaniel if he ever thinks about sleeping on safer streets, or cleaning up a bit and getting an apartment somewhere.
No, he says. This is his turf.
"I'd rather die where I know my way around. I'm out here breathing fresh air, and I'm not trapped in some apartment, cooped up and unheard of."
This is exactly what's so frustrating about Nathaniel. He can sound so sensible, even eloquent. But his irrational choices reveal the depth of his mental illness.
Nathaniel takes a cloth strap and lashes his shopping cart to the metal door of the storefront. Then he unpacks for the night, a ritual he performs while telling me the meaning of his music and his life.
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"My vision -- I hate to admit it -- but I'm going to have to do what Mozart did, and die. My vision is to stay in good with God and not worry about far-off stuff, just get across the street safely and be thankful. Honor thy mother and father, don't be disrespectful to people, be good, and maybe the music will take care of itself."
Not five feet away, a young ashen-faced man slumps down and lights a crack pipe.
Helicopters chop up the night, an amputee rolls by in a wheelchair and Nathaniel chases away cockroaches the size of Volkswagens.
"My god doesn't have a special name," Nathaniel says without my asking. "Beethoven could be my god."
He'd been to the library earlier in the day looking for sheet music, carrying a list of the pieces he wants. A Brahms double concerto. Tchaikovsky's Variations on a Rococo Theme for cello and orchestra. Mendelssohn's Third and Fourth Symphonies. Sibelius' Symphony No. 2. Strauss' "Don Quixote."
He couldn't find them, but was thrilled to come away with Camille Saint-Saens' Concerto for Violoncello.
"There's something like 18 or 19 notes in a single pickup," he says with a child's awe. "It's very pleasing that Saint-Saens had all those ideas and was fast enough to get this all down."
Out comes a whisk broom and Nathaniel, perhaps the most compulsively neat person I've ever met, sweeps the sidewalk where he intends to sleep.
"Have to get all this nasty business out of here," he says. He's particularly disgusted by cigarette butts.
The job done, he turns to me.
"Welcome to my humble abode."
Then Nathaniel reaches into the bottom of his cart and offers me a can of Shasta Tiki Punch soda.