Just when you thought every possible variation of the selfie had been explored, there's a new one in town.

The "donut selfie" made its online debut this week, courtesy of Karen X. Cheng, the ex-Microsoft employee responsible for the '100 challenge', which challenges participants to learn something new over 100 days.

To take the selfie, you just have to arc your smartphone around your head from temple to temple in a "donut" shape, making sure to capture the background in each setting.

Once you have a few "donut shots" you can edit them together to create a short video clip in which viewers have the impression of passing through your head and arriving in a different setting each time.

The overall effect is that the camera is "floating in space" around your head.

The entrepreneur has set up a dedicated website for the technique and created three step-by-step video tutorials for taking the perfect donut selfie, available online.