The 944 is an evolution of the the 1981 924 GTS which was itself a roadgoing version of the 924 Carrera GTR Le Mans car. The 924 came out in 1976, before the first RX-7.

This is a regular 924, note the similarity in the front end to the original RX-7:



This is a 924 Carrera GTS:



This is a 944:



This is a 944 Turbo/944 S2 (they look the same):



The SA looks like a 924, the FC looks like a 944. Who copied who (or whether anybody copied at all) is debatable. The biggest difference in styling was that the 924/944 was always a 2+2 with a window for the back seat while the RX-7 was always a 2-seater with a vestigal back seat added to certain variations.