Skip to content
flowss
Start freeChecking your session
Gantt & critical path templates

Teaching Case — A Start Date That Contradicts Its Own Plan

The defect this engine was built to catch, and it is invisible in every tool that draws what it is told. `cut` states it must start on 15 September; its own predecessors do not release it until the 29th — ten working days later. Both sentences are in the same document, both look entirely reasonable, and the drawing of the wrong one is identical to the drawing of the right one. The engine names the contradiction and counts the days.

Gantt & critical pathProject & PlanningGantt & critical path syntax docs
Template previewGantt & critical path
Magazine issue 47 — Gantt chart with critical path7 tasks; from 2026-09-01 to 2026-10-09, 29 working days; 7 on the critical path; 1 error, 0 warnings, 0 questions unanswered.Magazine issue 47Tu 1 Sep 2026 → Fr 9 Oct 2026 · 29 working days · 39 calendar dayscritical path: brief → write → edit → cut → lay → proof → pressshorten first: write (up to 10d) · edit (up to 5d) · lay (up to 4d)Sep 2026Oct 2026Tu1We2Th3Fr4Sa5Su6Mo7Tu8We9Th10Fr11Sa12Su13Mo14Tu15We16Th17Fr18Sa19Su20Mo21Tu22We23Th24Fr25Sa26Su27Mo28Tu29We30Th1Fr2Sa3Su4Mo5Tu6We7Th8Fr9EditorialProduction▲ Commission3d · shorten → 3d▲ Writing12d · shorten → 10d▲ Sub-editing5d · shorten → 5d▲ Cut to length2d · shorten → 2d▲ Layout4d · shorten → 4d▲ Proof3d · shorten → 3d▲ To press2026-10-09critical — zero floatnear-criticalhas floattotal floatmilestonenon-working daybaselineEvery check ran. 1 error, 0 warnings.✕`cut` states it must start on 2026-09-15, but its own predecessors do not release it until 2026-09-29 — 10 working days later. One of the two statements in this document is wrong, and the drawing cannotshow you which.·Tu 1 Sep 2026 to Fr 9 Oct 2026 — 29 working days across 39 calendar days, on a Mo–Fr week·one critical path, through 7 tasks — shortening any one of them shortens the project, up to the point another path becomes binding·to finish sooner, shorten `write` by up to 10 working days (then the next-longest path becomes binding); `edit` by up to 5 working days (the whole task); `lay` by up to 4 working days (the whole task).Anything beyond those figures moves nothing — the gain from taking δ days off a task is min(δ, the figure above), and it is zero for every critical task not listed here.

Make it your own.

title "Magazine issue 47"
start 2026-09-01
calendar mon-fri

section "Editorial"
  task brief "Commission" 3d
  task write "Writing" 12d after brief
  task edit  "Sub-editing" 5d after write
  task cut   "Cut to length" 2d after edit start on 2026-09-15

section "Production"
  task lay   "Layout" 4d after cut
  task proof "Proof" 3d after lay
  milestone press "To press" after proof