There are two small playgrounds in Washington Square Park which I didn't photograph; these images are from the Local Ecologist website[1]. Three playgrounds were built here in 1941 by the WPA[2,3]. One of these is still at the Fifth Avenue entrance to park; I don't have information about the other two.

1. At play in Washington Square Park, Local Ecoligist website, accessed 23 April 2018.
2. NYC Parks Department press release, June 5, 1941 : "The Department of Parks announced today that with the cooperation of the WPA it has begun the installation of three small marginal playgrounds in Washington Square Park, Borough of Manhattan".
3. NYC Parks Department press release, November 24, 1941: "The Department of Parks announces the completion of three small marginal playgrounds at Washington Square Park ... The work was performed by the Work Projects Administration from plans prepared by the Department of Parks".