Tupac, 2.0

Rapper Tupac Shakur, murdered in Las Vegas in 1996, was onstage on Sunday at a music festival in Coachella, California.

Most reports say a hologram image addressed the crowd and performed a duet with Tupac's old friend Snoop Dogg. But in fact this was a trick from the 1890s, coupled with state-of-the-art animation technology: A realistic animation of the late performer was projected onto an angled sheet of glass.

The details are technical but the effect was simple, and electric, even though the image was in two dimensions rather than three.

To be sure, many posthumous Tupac records and documentaries preceded this event, but it still breathes new life, so to speak, into the show business adage about death sometimes being a good career move.

The stunt was the brainchild of another rapper, Dr Dre. He and Snoop are now talking about taking their toy on tour. Indeed, this could open up a vast new industry: a mock poster for an "exclusively hologram" Coachella promises Michael Jackson, Patsy Cline and Mozart.

And of course "Holo-Pac" has a Twitter page ("Yo, I just wrote the first track since becoming a hologram. It's called 100101101010001110001").

Sense of humour, it seems, belongs firmly in the realm of the living.