[Tuba4]

And here is another recent question and new answer which impacts our discussion here:

Q. Will you please either clarify the ‘appendage’ definition, or state the legality of an appendage design with two separate arms that extend beyond a single frame perimeter edge and driven by a single/common mechanism inside the frame perimeter? The related Q&A responses seem rather ambiguous. Thanks.

A. As the other responses indicate, there is no formal definition of "appendage". However, one appendage (as allowed in Rule [G21]) would be one contiguous assembly. The contiguous part of the appendage must be outside the Frame Perimeter.