// the workshop · the flowchart

the flowchart

Build it with your own hands, then watch it run. Add a step or a decision, wire where each one leads — yes and no both — then hit run: a token walks the exact path you built, choosing at every fork you left open. Arrange it in a ring, or wire the last step back to the first — a real circular process doesn't halt. It just keeps going, which is the whole point.

edit mode: drag a box to move it, click to rename (× deletes). connect mode: click a source, then each target — decisions get yes (green) then no (red), a second click on the same target un-wires it. "ring" arranges whatever's on the canvas into a circle.

yesno
start
did today go as planned?
ground
name what moved
noted

// the science under it

  • flowcharts began as process charts. Frank Gilbreth presented them to ASME in 1921 as "the one best way" to see a procedure. (Gilbreth 1921)
  • then they became how programs were planned. Goldstine and von Neumann adapted the flowchart to coding electronic computers in 1947 — before code, a chart. (Goldstine & von Neumann 1947)
  • the symbols were standardized — the rectangle, the diamond, the terminal oval — first by ANSI (1970), then internationally as ISO 5807 (1985). The same shapes you just built with.
  • the deep result: three shapes are enough. Böhm and Jacopini proved in 1966 that any computable process — however tangled with jumps — can be rebuilt from just three control structures: sequence, selection, and iteration. Nothing else is required, ever. (Böhm & Jacopini 1966, CACM)

// the loop is its own kind

  • the pdsa cycle really does loop. Walter Shewhart framed quality control as a circle in 1939 — plan, do, study, act, then back to plan. Deming took it to Japan and insisted on that name; when Japanese engineers relabeled his wheel "plan-do-check-act," he called PDCA "the corruption" and said "how it ever came into existence I know not." Check just means inspect; study means actually learn. (Shewhart 1939; Deming, letter to Moen 1990)
  • closed loops stabilize machines and bodies alike. James Watt's 1788 governor swung weighted balls outward as an engine sped up, throttling the steam back down — a physical feedback loop, a century and a half before Norbert Wiener named the whole science of it "cybernetics" in 1948. (Watt 1788; Wiener 1948)
  • circular diagrams are an old habit, not a novelty. François Quesnay drew wealth circulating between landowners, farmers, and merchants back to its source in 1758 — the ancestor of the "circular flow of income" still taught today, a loop that runs as long as nothing leaks out. (Quesnay 1758)
  • the rule of thumb underneath all three: a chart that ends is a line; a chart that doesn't is a circle. Build one of each and the difference is exactly this — where the last step points.

// what this is not

This toy has no memory beyond where the token sits — it's a small finite-state walk, not a Turing machine. A Turing machine needs unbounded memory (a tape) alongside sequence, selection, and iteration; add that, and the same three shapes become universal — able to compute anything computable. (Turing 1936) This chart just walks the path you gave it.

// sources

Gilbreth 1921 · Goldstine & von Neumann 1947 · ANSI X3.5 (1970) · ISO 5807 (1985) · Böhm & Jacopini 1966, CACM · Turing 1936 · Shewhart 1939 · Deming, The New Economics 1993 · Watt 1788 · Wiener, Cybernetics 1948 · Quesnay, Tableau économique 1758.