Each card is a backlog item carrying story points (Fibonacci-like sizing: 1, 2, 3, 5, 8). Every simulated day, the team pulls cards from To Do into In Progress up to the WIP limit, then spends the day's velocity budget completing them — a card moves to Review once its remaining points hit zero, and to Done after one day in review.
Ideal burndown: R(day) = R0 × (1 − day / T)
R0 = total story points, T = sprint length (days)
Little's Law (queueing theory):
Cycle time ≈ WIP / Throughput
→ a low WIP limit shortens how long any one card sits mid-flow,
but throughput is still capped by team velocity.
- Sprint length — the time-boxed duration (T) the ideal burndown line targets.
- Team velocity — story points the team can complete per day; the shared budget spent across in-progress cards each tick.
- WIP limit — the max cards allowed in "In Progress" at once; a Kanban control that prevents context-switching and keeps flow smooth.
- Simulation speed — how many simulated sprint-days pass per real second.
If velocity × sprint length is well below the total backlog points, the sprint won't finish — exactly the signal a real Scrum team uses at Sprint Review to re-plan.