Trying to Make Sense of My Thoughts

How much or how little information do I need to convey for the viewer to understand what my icon means? One way I've learned to gauge it is by taking an object and making it more and more abstract until you’re left with just the bare essentials of that object. Doing it this way means I also have to assume my audience is able kind of do the reverse of what I did, and make some radical leaps to conclude that these basic shapes I have assembled in this way are able to convey a much different message than they appear. I really like the idea of Christoph Niemann's "Abstract-o-meter" from the TED Talk I found the other day, and with this knowledge I've been able to do a few things such as:

Create the world's least useful road sign.