It feels like having an itch right in the middle of his back, at the exact spot where his fingers can’t reach. Except this kind of itch starts from his fingers and spreads to his soul, so all he can do is try to alleviate a little of that itch.
So he collects gold, other precious materials, and talents instead, setting them aside for his son to use for his obsession. He only picks the best of the best, but even so, there’s almost too much for anyone to feasibly use for constructing a single building, but for this particular project – his itch – he doesn’t think any gift or donation on his part could ever be too much. (To be honest, he thinks it’s not enough, but then he has to remember to be wise because he’s a king and a king is supposed to be wise – if not for his sake, then for the sake of his people.)
It’s like drafting a recipe before choosing the exact ingredients and the chefs to cook the world’s greatest meal, so while he does have some influence on the final product, he will ultimately not know the final outcome as it’s still subject to change. Even most of his advisors look at him strangely whenever they discuss this project: their eyes tell him that they see someone a little too obsessed, but they allow it anyway.
He acknowledges the look, because he knows he can’t do much more than this. He knows the itch will only be relieved by his death, so he waits with the patience of a warrior, and watches his collection grow.