The Mystere falls into the dream car / flashy concept category. That's because it was almost entirely impractical and, with the exception of the tail fin color scheme treatment, was not predictive of future production Fords.
To set the scene, here are views of 1955-57 Fords featuring the J-shaped side trim theme also found on the Mystere. It first appeared for the '55 model year.
This is the 1956 version. It's a bit more gracefully shaped than the 1955 version, but still is rather awkward.
The best version of the theme was on '57 Fords where the aft part blends with the tail fin. We see this on the Mystere.
Alex Tremulis at the far right. The color separation side trim is awkward and does not enhance the car's appearance. It does relate to the trim on top-of-the-line '55 Fords and previews the link to canted tail fins that appeared for 1957. The placement of the passenger compartment seems too far forward. One reason for that is that the engine (which the Mystere actually lacked) would have been placed at the rear.