We use signs and signals in our work every day to tell us when and what work to do. Alarms ring at 11:30am to signal the duddle. A garbage bag is full, hopefully signaling to empty it. A full buffer zone signals a picker to help their neighbor.
There is a dash of art and some science to making a good sign. Probably most important, a sign should be appropriate to its purpose. Where you need speed, a sign should be able to be understood quickly. Think of highway signs, meant to be read at 70 mph: big, bold, easy to read, using a shared conventional language. Where speed is not as important... well, I'm not going to go there. I think speed is almost always important for signals and signs. If I make a sign that takes a minute to understand when another could get the job done in ten seconds I just wasted your time. In lean terms I just loaded you with a lot of over-processing. Signs are used over and over so the over-processing waste adds up. A lack of urgency shouldn't be an excuse to make a complex sign.
Here's a list of 6 sign and signal options, ordered from quickest to understand to slowest. I'm sure I'm missing some since I'm working from experience, not a referenc manual, so I welcome thoughts and additions. (They're also ordered in terms of how much information they can carry -- more on that in another post.) When you make a signal, start at the fastest to see if it can do the job you need. If not, move to a slower option. If it doesn't work, keep going. Also, consider if you can break the task into jobs that need simpler, faster signals.
Types of Signs, Fastest to Slowest
4. Graphic image
5. Pictorial image
Can you break the job down so it uses more simple signals instead of one complex one?