How to reconcile two seemingly conflicting ideas for setting up a workflow: a linear series of steps vs. parallelization of steps?
On the one hand, we have a reasonably typical Kanban board that facilitates a linear series of steps. Like the board seen in the background of the cover image of David J. Anderson's 2010 book Kanban: Successful Evolutionary Change for Your Technology Business. A single row of multiple columns represents a step or stage that a work item can pass through as it progresses towards fulfillment. On the board, a work item is represented by a card. The work item's progress is indicated by which column it's in on the board.
This helps us see progress and see which parts of the process are smooth and which parts could use some improvement. Great.
On the other hand, Jez Humble, co-author (with David Farley) of the 2010 book Continuous Delivery: Reliable Software Releases through Build, Test, and Deployment Automation, tells us to "reduce the number of stages as much as possible, and parallelize each stage as much as you can." https://continuousdelivery.com/2010/09/deployment-pipeline-anti-patterns/
This makes sense. Why wait to make a pie's filling until the pie's pastry is made? If both can be made simultaneously, the pie can go into the oven that much sooner.
But how can I represent an item's progress through parallel steps on my kanban board and continue to see which steps are running well and which are the steps at which progress is slowest?