Speaking of New York City, there’s the Solar Triangle by Athelton Spilhaus in the courtyard of the McGraw-Hill Building at 1221 Sixth Avenue (Avenue of the Americas). It’s aligned with the noon sun position on the summer and winter solstices
I’m not sure if you’re going to find a lot of “Easter Egg” solstice alignment items in modern architecture. If some goes to the trouble of designing, building, and aligning such a feature they generally want people to know about it. All the other examples I know about are pretty clearly marked and out in the open. There are several analemmas marked on the ground in several places,. including this one in Bergamo in Italy, and its indications are by no means subtle: