The Countach 50 is developed on the platform of Lamborghini's Aventador: it borrows the structure, the technology and the engine. Therefor, the Countach 50 could become reality.
1971 Countach Prototipo technical drawing
The Countach was reinterpreted to fit the Aventador platform; carrying the sculptural impact while beeing carefully scaled.
While the vehicle requires more cooling, the shoulders inlets raise and feed higher air volumes to the engine. The hot airstream is then evacuated through the rear lights. 
To improve aerodynamics furthermore, the rear spoiler raises from the body, increasing down forces. 
In this configuration, it resembles the later Countach's, with their prominent shoulder intakes and iconic rear spoiler.
All the light functions have been preserved to be working and legal.
The third light, or braking light, is nested within the glass panels covering the engine. When the vehicle brakes, the red light emits through the edge of the glass by internal reflection. Once off, it becomes invisible.
Indirected lightning highlight the two rear hot air outlets; creating an iconic rear light signature. 
A bar contains the other light functions, such as blinker, fog light and stop light.