The photo you see on these lines corresponds to a renovated castle near Brussels. I do not want to stop at the paintings on the wall, quite old (the one next to the door looks like Rembrandt, but I am very bad at recognizing faces) and difficult to combine, by the way, but in the detail they have had painting the openings of the doors with what are apparently kanji, or Oriental-like symbols (If anyone knows what it is to say, my knowledge of Japanese is reduced to the letters that mean "will continue").
With this simple decoration they have made sense of the openings that they were too wide, perhaps because the castle had wide partitions, and at the same time created an eclectic space. This decoration is perfect with houses of oriental type and does not hinder anything to those who have opted for the minimalism and in theory it is easy to execute, although I would not try it with markers unless you are working on wallpaper.
In this case, the idea has been of the architects Bateille & Ibens to those who were entrusted with the renovation of the place, which nowadays hosts parties, banquets and company meetings.