Minetta Triangle is just a few feet south of Minetta Green on 6th Avenue (see map) at Bleeker Street and Minetta Street. It might have been created at the same time as Minetta playground, or not. There is no New-Deal-era Parks Department press release that mentions it. The Parks Department website[1] says merely that the city acquired the parcel in 1925 and assigned it to Parks in 1945. The fact that it was not assigned to the Parks Department until 1945 does not preclude that the Parks Department created something on it during the New Deal[2].

1. Minetta Triangle - History, NYC Department of Parks website.
2. Minetta Green.