Identify the subject of this photo :)

[eti]

A quick bit of fun - identify the subject...

[ChristofferB]

Fabry-Perot interferometry? Not quite but each half looks the part

[eti]

Fabry-Perot interferometry? Not quite but each half looks the part

Nope.

Answer: What you're seeing is the two fresnel lenses of the flashlight which disperse and focus the dual colours of the two flashlight LEDs (they have two colours so software can adapt the camera flash colour temperature for different lighting conditions) on my Moto G7 Plus phone. The LEDs shine through these two tiny lenses, and I fired them into an old cine projector lens group (a stack of lenses designed to project cine film onto a screen), onto the wall.

https://en.m.wikipedia.org/wiki/Fresnel_lens