What is FLOWSIM?

FLOWSIM runs two software delivery simulations side-by-side so you can compare the outcomes of two different ways of managing work: Push (no WIP limits) and Pull (Kanban with WIP limits). Both boards receive identical team effort each day, so any difference in completion time is caused purely by the flow policies.

Colour Key

Workflow Stages

Every card moves through the same pipeline on both boards:

BACKLOG → ANALYSIS-WIP → ANALYSIS-DONE → DEV-WIP → DEV-DONE → TEST-WIP → TEST-DONE → DEPLOY-WIP → DEPLOYED → DONE

Each -WIP column is where active work happens. Each -DONE column is a buffer holding completed cards waiting to be pulled into the next stage.

The Core Loop — one day at a time

1. Roll effort — each player rolls a dice (1–6 points). The same rolls are used on both boards so the comparison is fair.
2. Pull cards forward — on the PULL board, cards are pulled into WIP columns only when there is capacity (WIP limit not reached). On the PUSH board, cards move forward unconstrained.
3. Assign players — each player is assigned to the highest-priority unassigned card in their stage column.
4. Apply effort — each player's rolled effort points are spent against their card's remaining work. A card may be partially or fully completed in one day.
5. Advance completed cards — cards with zero work remaining move to the next stage automatically.
6. Handle blockers & defects — blocked cards skip their turn. Defective cards in TEST-WIP are sent back to DEV-WIP for rework before they can advance again.

Flow Policies

Policy	PUSH board	PULL board
WIP limits	None — unlimited cards in every column	Enforced per column (adjustable with the ± buttons in each column header)
Work item priority	Newest item first (LIFO)	Oldest item first (FIFO)
Backlog replenishment	Pushed in continuously	Pulled in only when there is room in ANALYSIS-WIP
Rework (defects)	Defective card moved back to DEV-WIP; dev effort consumed on rework, then remaining effort continues new work	Same — rework is prioritised first, then any remaining dev capacity is used for new work

Effort & Story Points

Each card is assigned a random effort estimate at creation time (converted to Fibonacci story points: 1, 2, 3, 5, 8, 13…). Each stage of the pipeline has its own estimate, so a card may take 2 points of BA work but 8 points of DEV work.

A player's dice roll determines how many effort points they contribute that day. Points are applied to work remaining on the card. When work remaining reaches zero the card advances. If a player has leftover effort after completing a card they do not carry it to another card — effort is lost at the end of each day.

Blockers

Any card has a 30% chance of becoming blocked when it enters a WIP column. A blocked card is highlighted magenta and cannot be worked until the blocker clears (randomly after 1–7 days). Blockers represent external dependencies, waiting for decisions, or environment issues.

Defects

Any card has a 30% chance of being found defective when it reaches TEST-WIP. A defective card turns red and is sent back to DEV-WIP for rework. Once rework is complete it returns to TEST-WIP and must pass testing again before it can advance to DEPLOY.