The cars in question are, on the one hand, two versions of Alfa Romeo's Alfasud ("Alfa South") and on the other, Volkswagen's fist-series Scirocco. Links dealing with the Alfasuds are here and here. A Scirocco link is here.
All the designs were by the ItalDesign firm headed by famed designer Giorgetto Giugiaro (1938 - ). For that reason, it shouldn't be surprising that similar-vintage designs were created in the same spirit. What is somewhat surprising is that the designs are quite similar. Shall we take a look?
The TI, a two-door version of the initial Alfasud, appeared towards the end of 1973, according to the Alfasud link above.
Sciroccos went on sale in 1974, but their development timeline probably overlapped that of the TI to a considerable extent. The TI is slightly more rounded than the Scirocco and the rear side windows are shaped differently. Both cars have ridges around their wheel openings as well as a crease running along the upper sides. Grille ensembles are full-width in both cases, and simple in form. Details such as these aside, the Scirocco can be characterized as basically being a crisper-looking TI or the TI as a softened Scirocco.
A couple of years later, Alfa Romeo introduced a sportier two-door Alfasud, the Sprint model. Again, Giugiaro was responsible.
The Scirocco got a restyling for the 1981 model year. The Wikipedia link above states that this time, the designer wasn't Giugiaro, but instead Herbert Schäfer, chief designer of Volkswagen's styling section. Even though Giugiaro was out of the picture (so far as I know), the designs are still surprisingly similar, though this time, it's the Scirocco that has the slightly softer appearance.