It's so serious every time I write my John Hancock like
Could damn near see Detroit, I see you
from Lupe Fiasco – Failure Lyrics on Rap Genius
Nowadays, record producers take it seriously when Lupe signs a contract (“John Hancock” means signature, since Founding Father John Hancock was the first one to sign the Declaration of Independence)
Lupe plays with the word serious, pronouncing it “Sears” as in Sears Tower, the tallest building in the country (located in Chicago, but from the top you can almost see Detroit).

Going along with the word play from “serious” to “sears” as in the Sears Tower, the John Hancock at the time this song was released was also the 2nd tallest building in the U.S. as well as Chicago.
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