Ah, ok. Yeah that was what I was imagining too, sorry for thinking you meant something else.
There are a couple of hiccups that system might encounter with the rest of the current concept. For one thing, it’s meant to be possible to upgrade flagella to cilia and vice versa (as well as cilia upgrading to lamellipodia). If the two were represented differently, this wouldn’t be possible. Also something to consider is how different types of covering would interact with each other. Cell walls would obviously prevent any other type of edge being applied (including flagella or pili), but would cilia and engulfing edges/flagella/pili be mutually exclusive?
Thinking about it, with cilia/cell walls being added in a completely different way if we change this system, there isn’t really any need for external organelles. Flagella, pili and agent secretors would be placed just like all other organelle types, although the editor would need a modification to allow the player to set the direction the external organelle points (possibly in the appearance tab if cilia and cell walls are now handled there, since the membrane and external organelles will be drawn on).
The only possible problem may be engulfing edges, but they could still be fixed too. They could be placed as full hexes, like flagella and pili, and would just apply the engulfing edge to the area of the membrane which covers them (they don’t need a 3D model or anything, just a different shader for that area).