Seeing the above, I immediately thought of something I'd seen for the first time and photographed just a week earlier:
St. George's Play Yard is adjacent to St. George's Episcopal Church on East 16th Street, only a half block from Stuyvesant Square in the Gramercy Park area. It is also next door to the Jack and Jill School and the Friends Seminary School. The play yard is striking for being the antithesis of contemporary safety-first playgrounds: it is steel instead of plastic, angular instead of soft, muted instead of colorful, and so forth.
Formally the play yard and TIMO are quite similar, given that they each have stacked shapes (triangles, squares, parallelograms, octagons), are finished in brown, and have ladders for climbing/access. This last aspect is what I find most interesting, since the inclusion of ladders (and railings) on TIMO points to the roof being accessible for visitors. Ito's design is definitely playful, and while I'd wager he wasn't influenced by St. George's Play Yard he's basically created a building-size playground.