3×1 landscape mode
5×1 portrait mode
The first picture uses Samsung S27A750D, while the second one uses Samsung S23A750D, they removed the bezel that’s why its so thin at the edges.
If you plan to setup a triple monitor, I suggest you get 1 IPS monitor and get 2 smaller screens in portrait mode – which is what I’ll be doing, 27″ in the middle and 2 17 inches (1440×900) on both sides in portrait mode. If you put two 27″ at the sides it will be sort of stretched on appearance at the satellite monitors when gaming.