Example 01 · E-commerce
Online store checkout
A shopper's journey from landing on the store to a confirmed order. The User Activities read left to right; the first Release is the thinnest path that still lets someone buy.
Release 1 · MVP - a customer can buy one item
Later - conversion & retention
The backbone is the user's journey, not your features. Each column is a User Activity; reading across tells the whole story.
The first Release is the thinnest end-to-end path. Everything above the divider must ship together to deliver a working purchase.