These are colorised permutations of the existing black-and-white New York state route marker.
Like the first series, the state routes would adopt the colors of the 1970s NYS license plates and the county route markers would adopt the US FHWA standard county road colors, with two variances: there would be a watermark in a slightly paler blue, and the route number would be in goldfinch yellow, not US FHWA standard Spanish Orange (warning sign Yellow).
Two-digit route marker, square.
Three-digit route marker, short rectangle (Ht. by 5/4ths Ht.).
Three-digit route marker, long rectangle (Ht. by 3/2nds Ht.)