Scissor Semaphore -- willowings

[Prompt: A form of silent communication]
I just barely submitted Willowings' whiskers for WASC, before I looked at the other prompts. Then I saw this one: "A form of silent communication," and I knew I had to keep going with willowings.
Last article, I talked about the feelers branching from their heads, and the nuanced communication that can come from those. But my tree-guarding people have a second speech I haven't even touched on.
As mind-blowingly lovely as the feeler languages are, those methods work only at short distances. Nobody's vision is keen enough to pick up on the nuances of a hundred skinny branches subtly swaying to a 3/4 rhythm. And willowings spend a lot of time at "outpost" range, so they need another way to talk to each other.
Enter Scissor Semaphore (working phrasing). This starts with the whole reason willowings needed to develop hair-fingers in the first place: they ain't got no hands!!! Willowings are mantidoids, and that body plan extends to their front limbs, which resemble a more serrated lumber-saw version of a praying mantis' raptorials. The joints bend a little differently, and the scissors are used more for climbing and wood work than hunting, but otherwise they are much the same. They fold and hinge in a Z formation. That Z can be configured into a variety of positions and angles, and that is the basis of Scissor Semaphore.
Willowings spend a great share of their time in trees, equal parts guardian and lookout for their assigned trunk post. When someone needs to communicate something simple to her fellow guardians, she will climb to a visible branch, or even the crown (exposing and risky, so only when it's really important), and do a little "look at me" dance. Then she will give her message in Scissaphore, customarily repeating it six times if she has time. Sometimes subsequent repeats will add detail, but the critical heart of the message is said from the first, and preserved throughout the repetitions.
Now that I've got the purpose & concept down, I need to actually develop a linguistic system for Scissor Semaphore. Will they be based on letter-type symbols? Warning-oriented messages (i.e. "dragon above behind you")? Commands? Maybe I'll take a drop from the bees' hive and dragonflies, have a scissor-Z's angles communicate the position of something with impressive precision. They have the software for it. I'll have to do a bunch of signal history research and work that out later. Chewing on this.