or horizontally forwards (scissor), a butterfly door features a lower and upper hinge operating on separate axes of rotation, meaning the door opens up and forward. From the front, this looks like ...

Both scissor and butterfly doors can be ... "hinged at the front edge behind the front wheel," and describes them as "a cross between a conventional door and a scissor door." ...

Reversing the butterfly’s calamitous decline requires ... for their specific locality and then deliver them to their front door. To fortify these individual commitments, we should normalize ...