The idea was to create a commemorative coin to celebrate the work of H.G. Wells, the British writer, historian and sociologist best known for the novels "The War of the Worlds" and "The Invisible Man," on the 75th anniversary of his death.

But the 2-pound (roughly $2.70) coin that the Royal Mint in Britain unveiled has irked some fans of Wells, who quickly spotted what they described as botched imagery in the coin's design, which was inspired by the author's books.

For instance, the Martian machine that Wells described in "The War of the Worlds" as "a monstrous tripod" has four legs instead of three. And the image of the Invisible Man on the coin has the character wearing a top hat and not the "wide-brimmed hat" that Wells described in his book.

Holly Humphries, a digital artist from Oxfordshire, England, said she noticed the mistake the day the coin was announced by the Royal Mint.

"The tripod is an iconic, famous thing in fiction for over 120 years now," she said, "and to make that mistake shows an incredible lack of familiarity with the work, especially when you're trying to honor the writer with such a coin."

Adam Roberts, a vice president of the Wells Society and a professor at Royal Holloway, University of London, was equally irked by the Invisible Man's top hat.

"So it's two for two," he said of the coin, which will be issued later this year.

Wells, who was considered an outstanding literary figure of his time, is best known for his science fiction novels. He died in 1946 at the age of 79.

In announcing the coin, the Royal Mint said it was "celebrating the imagination and enquiring mind of a man who helped shape the world we live in."

The coin was designed by Chris Costello, a Boston-based graphic designer and illustrator. It depicts the four-legged alien machine with the Invisible Man in the foreground. The coin's visuals also include a partial Roman numeral clock, a nod to "The Time Machine," Costello said on his website.

He said that "the final design combines multiple stories into one stylized and unified composition that is emblematic" of Wells' work "and fits the unique canvas of a coin."