> In particular, any series of computations that can be represented as a directed graph, e.g. a streaming data workflow, or state machine, is much more easily understood pictorially than textually.
As long as it is very simple. Electronics already have a highly developed visual language for describing their functions - but if what was going on inside every chip was illustrated just as what was going on between chips, it would be entirely unintelligible. Instead, any visual representation is at a particular scale, and well known portions are represented as blocks with cryptic textual notes next to each interface (ACK, EN, V0+, CLK, PT2, HVSD, WTFBBQ, etc.), labels to identify company or type, and an expectation that you know what they do or can find out on your own (and not an expectation that you understand how they do it.)
Anything simple enough to be completely expressed in human-comprehensible pictures should be exposed to the user and modifiable (even if not by using pictures, but forms.) I totally agree, if that's what you and this article are trying to say. My experiences in trying to encode actual human workflows in BPMN have taught me that when using pictures it's harder to express things of any sophistication than in words - because of words like "with" and "each" and "all", "if" and "when," and because of ways things change over time, and because of separate but overlapping/interacting flows that languages can express easily but pictures not so much.
In pictures, that involves looking all over your picture for different things, trying to figure out how to draw lines to them; if the condition is once or twice removed from the object of the search, it involves trying to untangle massive knots with your eyes and memory.
Theoretically, that is. What it involves in practice is scrawling words all over your picture (just like in a circuit diagram.) Words that express the same types of relationships over time and type as the picture is trying to express projected onto a plane, words that could be easily expanded to include those relationships and eliminate the 18 types of lines, the 25 types of shapes, the 12 types of shape borders, the 16 color schemes and the long list of rules for connecting them that had to be invented to avoid coming up with a textual syntax.