Lachlan Turczan is an American artist who works with light and water. He recently posted this video of a temporary piece he created. Hit play, watch it for a few seconds, and think about it. Can you figure out how he pulled it off?

Turczan explains:

"An ellipse of light reflects off a heated pool, casting a rippling circle onto a transparent screen [that is] superimposed on the landscape."

The technique is similar to an old theater trick called Pepper's Ghost, invented by 19th-century English scientist John Henry Pepper. Here's an illustration of the technique:

Image: Public domain, from "Le Monde Illustré, no. 406, 21 January 1865, p. 48. Provided by Bertrand.

If it's not obvious, a large piece of glass is mounted between the audience and the stage. The woman in front of and below the stage, unseen by the audience, is brightly illuminated, and her reflection appears on the pane of glass. Due to the angle of the glass, she appears onstage as a ghostly figure. The technique was used for plays that involved ghosts.

The technique above is not the only trick up Turczan's sleeve; check out the impressive pieces on his Instagram.