Butterfly doors, also called vertical doors or dihedral doors, are a type of door often seen on high-performance automobiles. They are similar to scissor doors, but while scissor doors merely tilt forward and up, butterfly doors also rotate as they move forward.
The McLaren F1, Alfa Romeo 33 Stradale, Saleen S7, Enzo Ferrari, and the Mercedes-Benz SLR, among others, use butterfly doors. The Toyota Sera was a limited-release car designed exclusively for the Japanese market which used this design. Due to its unusual design, some enthusiasts in Australia, New Zealand and Great Britain have privately imported the Toyota Sera. It is only available in right-hand drive configuration.
Koenigsegg uses a "dihedral synchro-helix" system for their vehicles (known in the custom-car world as "raptor" doors) which seems to combine the advantages of all the designs though with considerably more mechanical complexity.