For more than 20 years, an anonymous person has been busily sinking into the streets of Philadelphia a riddle about resurrecting the dead on planet Jupiter.

The Toynbee Tiles, named after the mid-20th century historian and philosopher Alfred Toynbee who is referenced in the tiles, are cryptic messages embedded in city asphalt around the country. They seem to originate from Philadelphia.

Rapper Raj Haldar, who goes by Lushlife, sees them all the time as he walks around the city.

"It's clearly distinct from street art," he said. "It doesn't have artistic motivation. I think it's all about communicating a singular idea."

Lushlife, who is also a producer, has written his magnum opus about the Toynbee Tiles: the 10.5-minute, four-movement "Toynbee Suite," being released as a free audio stream and available for download here.

The Toynbee Tiles were the subject of the documentary, "Resurrect Dead: The Mystery of the Toynbee Tiles" (2011), which won an audience award at Sundance. Lushlife said he didn't see the documentary until his recording project was well under way.

For Lushlife, the architecture of a four-movement hip-hop opus came first, then he searched for a subject to fill it with. The tiles are written in four lines, all variations of:

TOYNBEE IDEA
IN KUBRICK'S 2001
RESURRECT DEAD
ON PLANET JUPITER

Toynbee "laid out this idea that though religions and cultures across time and geography had always promised an afterlife, that afterlife had not come to pass," said Lushlife. "But it would thanks to technology. For some reason, that would happen with reconstituted molecules on Jupiter."

The four movements of Lushlife's loosely correspond to the four lines of the message.

"Starting with walking down the street with a bop, and seeing these things," said Lushlife, describing the loping rhythm of the first movement. The beat is so casual and every so slight off that it almost feels languid.

"Once you are indoctrinated in the classic hip-hop of the first movement, it was important to introduce something propulsive," said Lushlife. "The listener, by minute four, should realize this isn't your average rap song."

The second movement opens with a loop of "Stop. Dave. Dave, stop," the lines famously said by distraught computer HAL in Stanley Kubrick's "2001: A Space Odyssey."

"There's an alternate universe where this is a complete disaster," said Peter English, the deputy director of Weathervane, the nonprofit recording company based in Philadelphia. Weathervane's Shaking Through project invites select artists to spend two days in its recording studio in Fishtown to record and mix one song, free of charge. The community-based music program relies on donations and grants to record and release new music.

A most ambitious recording

In five years, Shaking Through has produced 40 songs. English says this is by far the most ambitious. With 18 musicians, a string quartet, star producer RJD2, and only days to make a 10-minute song, there was plenty of room to fail.

"Every step, I felt that when the bar was raised, Raj met it," said English. "It's my job to pull the plug if I don't see that happening. I didn't have to."

True to form, Lushlife made the track lush. The Dark Horse Orchestra was called in to record string interludes between tracks, RJD2 came in to produce the second movement ("Raj wanted a classic hip-hop feel," said English) and the song plays out with a gentle piano and clarinet coda.

"That's how all rap songs end, with two minutes of clarinet," laughed Lushlife.

The first-person perspective of the lyrics flips between Lushlife and the mysterious tiler, about whom Lushlife knows nothing except for his entrenched, decades-long focus on a singular ideal.

Regardless that the ideal might be barking mad, Lushlife found some kinship with the nameless tiler.

"Both of us are tirelessly pursuing one static goal in the face of glacial time," said Lushlife. "For him, 20 years of furthering Toynbee philosophy. For me, how I want to make rap records. I really do relate to the Toynbee tiler."