I'm currently working on a project with a windowless bathroom and came across this great way of faking it - a back-lit shoji screen. Such a cool idea by Mark Brand Architecture. Then I noticed the stone cladding on the wall and bath panel. I've been seeing this idea quite a bit recently, including when design hero Abigail Ahern recently clad the interior walls of her garden cabin with dark grey slate (top right picture). I love that it brings the outside inside and gives the room immediate texture and cosiness.
get the look
These are the Hartington Tiles, £149 per m2 from Fired Earth.