Manhattan Apartment is Decades-Old Children's Puzzle

"Surreal Estate: Turning a Manhattan Apartment Into a Puzzle Palace"
Wired (April 20, 2009)

"The first hint that something was up came in a letter stamped "Lost Post." It was addressed to the family of six who had recently moved into the sprawling Fifth Avenue apartment—and was apparently written by a former occupant who had died decades earlier. Inside the envelope was a poem full of riddles, the solutions to which were all around them: The home was filled with puzzles that had been covertly installed during an extensive renovation...."

"...The elaborate project started with a casual aside. 'Can we do something for the kids?' Clough asked his client, the CEO of a private equity firm, when he began work on the $1 million-plus job. Nothing complicated at first, just a few hidden lines of verse. But soon the carpenters were carving ciphers into radiator covers and adding secret compartments to the credenza...."

Eight photos come with the story. One caption reads, "A cherry tree mural in the kids' bedroom doubles as a map of Central Park."