The Ford Mustang is so much more than just another model the blue oval produces. This car has come to define its breed and is now a staple of the automotive landscape, both in America, and abroad. You only need to say 'Mustang' and most people know you're talking about that particular model of car, but the model's inception and evolution wasn't always quite so clear.

Over the decades Ford experimented with many different paths for the Mustang, many of which never made production. These concept cars are a fascinating look at what sort of future the car could have had in a parallel universe.

In the early 1960s Ford wanted to introduce a relatively affordable model that the everyman could aspire to own. Several design studies were carried out to explore what exactly the as yet unnamed Mustang model would be.

The Avanti concept was a coupe based on the new compact Falcon platform, which incorporated a fastback design and a hatch opening. An interesting quirk was the inclusion of two rear-facing passenger seats.

Another concept worked on simultaneously to the Avanti was the larger Allegro. No relation to the Austin of the same name, this car contributed the now familiar silhouette of the pony car.

The Avanti concept continued to evolve, but as Studebaker had just introduced a model of the same name, it was rebadged Allegro. But wasn't there already an Allegro concept? Yes, but by this stage it had been discarded, leaving the nameplate vacant.

The Allegro / Avanti had ditched the hatchback opening and replaced its rear seats with a more conventional layout by this point. Sadly, this is as far as the design went.

As well as the other concepts, Ford looked into a two-seater model in the same vein as early Thunderbirds. While the Thunderbird was very successful, it had grown up and was far from the small sports car it was originally intended to be.

Its two-seater concept made use of a removable hardtop and folding canvas roof.

When the Mustang was launched in 1964 it was an overnight success. Ford began work on how to capitalise on the model's popularity, considering several variants that included this more practical four-door example.

If you thought the four-door Mustang variant was strange, check out this wagon that was seriously considered for production. With just two doors we'd say it was more shooting brake than wagon, but either way, it wasn't to be - shame!

Keen to produce a high-performance variant of the Mustang, Ford's 1967 Mach 1 concept hinted at what engineers wanted the Mustang to become, featuring active aerodynamics, a more rakish profile, and a 302ci V8 engine.

While the Mach 1 that eventually hit the market was a mighty muscle car, it was far less revolutionary and only carried the echoes of its handsome concept predecessor.

This car is spoken about as if it were a myth, but a mid-engined Mustang concept car did surface in 1967. Designed to potentially replaced the Shelby Cobra, this GT car never made it to the showroom due to its manufacturing process being too costly.

Two running Mach 2 prototype cars were built, with Ford even allowing journalists to sample the car in motion.

Come 1967, Ford designers reinstated the Allegro name for a new concept car built upon the original fastback mock-up. They chopped the windscreen and removed the roof to create a speedster model that certainly captured the attention of onlookers. It was titled the Allegro II, in honour the concept on which it was based.

This concept car bares little resemblance to any generation of Mustang, but fans of Australian Fords might be able to place it. Built for the 1970 Chicago Auto Show, this Mustang heavily influenced the Ford Falcon XB.

The 1980s were difficult times for muscle cars, thanks to the oil crisis and government regulations. Manufacturers were downsizing fast and Ford created the controversial Fox-body Mustang. To keep disappointed fans on-side, Ford considered entering the exciting world of rallying with one.

This car was designed by Ghia as the basis for a potential homologation special that never materialised. It was one inch wider than a standard Mustang, but 5.6 inches shorter, giving it more compact European proportions.

Ford was hard at work creating an all-new Mustang to form the bases of fourth-generation models. It wanted to reincorporate many of the traditional styling traits lost in the previous car, and so a series of concepts were made.

The first was deemed too soft, so designers created this aggressive incarnation that was lovingly dubbed 'Rambo'. Predictably, this concept was seen as being too over the top, with the final design ultimately splitting the difference.

This 1992 convertible model suggested to motor show attendees that change was afoot for the fourth-generation Mustang. It hinted at some of the future design language, but did little to resemble the up-and-coming Mustang.