Wayfinding for Te Matapihi ki te Ao Nui, the Wellington Central Library, included access to and from the basement. This area extends under the whole of Te Ngākau Civic Square, connecting through to City Gallery Wellington Te Whare Toi, Te Whare Whakarauika Town Hall, and the City to Sea Bridge.
I had already completed a wayfinding strategy for Te Ngākau Civic Square, including the entrances into that basement. It's a working space—vehicle movements including large trucks on stage access, council fleet access, dry and secure public bike parking in the middle of the city, and people needing to walk through all of it to get where they're going. Safety was the original brief. The opportunity was to make the public-facing experience joyful.
The architects had already made a bold move, painting the concrete columns that do the actual work of earthquake strengthening. Any intervention needed to sit inside that decision, not compete with it—and it needed to be something roadmarking contractors could actually install, since that's who was doing the work.
Yellow—a genuine safety colour, and also Wellington City Council's brand colour—painted across the public route through the basement reads instantly as walk here and avoid the remaining concrete areas, and it lands as a proper shock of colour against those pink columns. 
The first hand-drawn and hand-cut templates, done by the linemarking crew, were genuinely admirable work—but not crisp enough for the bold use of typography this space needed
The fix was simple: introduce the linemarking team to a CNC router and better templates. Combined with a short lesson in kerning, the basement was completed using the trades and tools already on site, rather than inventing new ones.