Actually, I did spend a lot of the day looking out the window.
I didn't see anything yellow. Nor did I come up with a good solution.
But, I spent the last hour of the day with a bunch of other people trying to come up with something.
None of them came up with anything I hadn't. None of them came up with anything that works with the constraints I have.
So, I don't feel so stupid now.
CEO is still mad about it, but at least the people saying "how could you get something so simple wrong?" have shut up.