[anon4]

Given the low reflectivity of the moon, can't we "just" lay down a lot of mirrors in the shape of the letters we want?

Build a rocket ship that makes a flyby of the moon, drops some mirrors and returns. Maybe it could rendezvous with the ISS to get a fresh supply of mirrors and we send the mirrors to the ISS by conventional means.

And when I say mirrors, I am thinking of really thin ones. Really, just giant sheets of aluminium foil. I suspect they'll naturally drift around and degrade over time, giving people something to think about as a poignant metaphor of some artistry thing.