I can see since the last update a new fifth tower has been added to the 4 towers in this northern part of Madrid. It´s name is Caleido tower. It will be a 180 meter tower (Torre Cristal is 250 meters high) The architects (Fenwick Iribarren and Serrano-Suñer Arquitectura) claim their inspiration comes from Kubricks 2001 A Space Odyssey movie - the monolith on the film.
https://makespain.com/wp-content/upl...eido-tower.jpg
Credit: Makespain website

In my view the building contrasts too much with the 4 towers. When the project was presented the images used illustrated a building that seemed almost as high as the 4 towers (perspective played a tricky part on this)

^ Yeah, well, now that those 4 matches have been there for years in the skyline, they need to build a lot more anyway.
It would be embarrassing if they didn't.

This is near the Chamartin station? I stayed right near there the last time I was in Madrid.

Exactly, very close to the station of Chamartin

Always accounting firm logos at the tops of the towers in the big cities of Spain and South America. KPMG. PWC.

They do the same in Paris La Défense, to be honest. Not those accounting firms you mention, but large banks, insurance or consulting companies and corporations of the energy industry surely like to have their brands stuck to the top of a tower over here.
It's not always sexy, to say the least. See this for instance... Yuck. They could do better than that, eh.

those logos actually look pretty nicely done here.

i remember when travelors insurance put their umbrella logo on a building downtown facing uptown. the whole city wanted to murder them. it was lit up and you could see it from westchester. and the poor birds. they unlit it for awhile and finally took it down thankfully. ugh. so corporate logos on office buildings can not only be unattractive, they can be horribly annoying -- here is the wiki:

388 Greenwich Street
Umbrella icon
The building was well known by New York residents for its large 50 ft (15 m)-by-50 ft 4-story red neon umbrella mounted in May 1997 near the top of its north-facing side that some found emblematic and others distracting.Complementing this neon sign, an iconic, steel 16-foot (4.9 m), 5,300-pound (2,400 kg) red umbrella sculpture also stood outside 388 Greenwich St at street-level. Both have been removed from the building, the latter in the summer of 2007, as part of a deal between Citigroup and St. Paul Travelers Companies which acquired the logo.