Go ahead and mock White House Chief of Staff Jack Lew for his odd, loopy signature — the one that will likely grace dollar bills if, as expected, he becomes treasury secretary. But be gentle with him, please.

Turns out, the hard-charging Lew probably has a softer side, says one handwriting analyst.

The roundness of the characters in Lew’s impossible-to-read John Hancock indicates that he just might be the cuddly sort, says Kathi McKnight, a professional graphologist, meaning someone who gleans people’s personality traits from their writing. Such strokes are common among those who prefer a “softer” approach to problem-solving, she says.

The signers of the Constitution, by contrast, used very strong, angular lettering, McKnight notes — not that leaders throughout history haven’t used circular strokes like Lew’s. Like who? “Well, Princess Di had very loopy writing,” she says.

And the fact that Lew’s signature is illegible may mean that he wants to keep his true identity unknown. “People with illegible signatures ... like to keep some things private,” she says.

Perhaps Lew will want to spruce up his signature before it makes its prime-time debut, as his predecessor did. Current Treasury Secretary Timothy Geithner told NPR last year that he had to work on his penmanship to make his name legible enough to befit its place on U.S. currency.