What kind of project? It's not his thing exactly, not like how painting is, but there's a beauty in a well designed and constructed building that he's been sorely missing ever since leaving Andoran, that he hadn't ever really thought about it until he felt the lack of it most places. The temples are mostly fine, and some of the older buildings in the Kenabres city center, but there's a grim practicality to all the walls and fortresses and most of the new construction. He'd just been talking about it with a new friend of his from Cassomir, Aron Kir, he's got some ideas about how to fix Drezen's architecture so they can't have a repeat of what happened last time once they retake the city and it'd be the perfect time for a glow up.

Hopefully it's not too hard to talk her out of just using wall of stone for everything, though, it gives the whole place such a drab monocolor. 

Well, this is all hypothetical right now, you understand, but ideas on how to make Drezen more defensible once they have it are very welcome! As is aesthetic consulting; her headband is great for designing buildings that won't fall down but worse at designing ones that will look cool. She's not sure if there are any spells for putting up entire buildings in a day with magic that aren't basically all stone, but you can definitely make stone look cool! She's seen pictures of, like, Notre Dame and stuff. It's just not what she's personally good at.

Oh good, he's sure they can come up with something then. In Andoran it's mostly done by humans, with magical assistance from ant haul and sometimes enlarge person, but surely there's got to be something else out there that would work. He can talk to some people about good paints for it, worst case scenario, but it's better to save that for the things that really need it and allow more creativity elsewhere.

She knows this one! Or at least, knows some answers for it, since all well-sunstantiated upper bounds for the number of possible spells thus far established are very high. In addition to conjuration spells like wall of stone and iron, there are also a number of transmutation spells like stone shape, telekinesis, or grand polymorph that might help in constructing buildings. There are a number of demons that get access to Telekinesis especially, and Nenio is very interested in how good demons are at architecture, particularly how they match up to the genies once used by the Suntan Azizal III, who made use of his outsiders to perform impossible feats of construction at record pace. (Historical records suggest that the resulting works were incredibly beautiful, but due to the outsiders cutting corners in their work and the passage of time only a handful of the most iconic structures are still around today to compare).

...If they're talking specifically securing Drezen then she has a bunch of ideas for puzzle corridors to put in place around important buildings, though she'll have to adjust some previous designs since it's not underground or in a demiplane.

The problem with puzzle corridors is that their allies aren't strictly and universally cleverer than their enemies. But she'd totally take a puzzle corridor outside, like, her office, if she ever ends up having an office that isn't in a tent and if there's a way for people who need to see her about stuff to ask to temporarily disable it.