It turns out there's not a lot of logic after all in the belief that it's against the law to Vulcanize Wilfrid Laurier's likeness on the $5 bill.

The death of Leonard Nimoy last week inspired people to post photos of marked-up banknotes on social media that show the former prime minister transformed to look like Spock, Nimoy's famous Star Trek character.

The death of Leonard Nimoy last week inspired people to post photos of marked-up banknotes on social media that show the former prime minister Wilfrid Laurier transformed to look like Spock, Nimoy's famous Star Trek character. (Tom Bagley/Canadian Press) For years, Canadians have been wielding pens to draw Spock's pointy Vulcan ears, sharp eyebrows and signature bowl haircut on the fiver's image of Laurier.

Contrary to what many believe, the Bank of Canada said Monday it's not illegal to deface or even mutilate banknotes, although there are laws that prohibit reproducing both sides of a current bill electronically.

Nonetheless, bank spokeswoman Josianne Menard pointed out there are reasons to resist the urge to scribble on bills.

"The Bank of Canada feels that writing and markings on bank notes are inappropriate as they are a symbol of our country and a source of national pride," Menard wrote in an email.

Long life and prosperity might also take a hit: Menard said disfigured bills may not circulate for as long and risk being rejected by retailers.

Following Nimoy's death Friday, social media users posted their own versions of Laurier's Vulcan makeover to honour the actor.

"Spock your $5 bills for Leonard Nimoy," a group called the Canadian Design Resource tweeted alongside its depiction.

The online images of the altered bills circulated widely and attracted international media attention to something many Canadians were already familiar with.

It wasn't exactly a place that no Canadian had boldly gone before.

Calgary artist Tom Bagley, who posted his own Spock-Laurier hybrid on Facebook and Flickr after Nimoy's death, described it as an old bar trick to impress the waitress

He compared it to folding the $20 bill along the Queen's face to make her smile or frown.

Bagley said he had no concerns about any potential legal issues over defacing the banknote. Besides, he said, he drew his with a pencil crayon, which can be erased.

"I don't know anyone that's gone to jail for it," he said in an interview.

"I always thought it was OK as long as the numbers were intact — it still counted as money. That's what I heard. Because stuff happens, like say you spill spaghetti sauce all over it or something like that."