The Analog Refactor Playset: Build a Desk-Sized “Toy Model” of Your Codebase Before You Change It

Big refactors are scary for a reason: once you start moving pieces around in a large codebase, it’s easy to lose track of dependencies, hidden side effects, and accidental complexity. But what if you didn’t have to start in the real system at all?

What if you could first build a desk-sized toy model of your architecture—something small, manipulable, and safe—so you can explore options before you touch a production branch?

That’s the idea behind the Analog Refactor Playset: treating refactoring as a modeling and design activity, not just code editing. Instead of rushing into large-scale changes, you first build a toy model of your system’s architecture using diagrams, sketches, and simplified code. Then, once the design feels solid on the desk, you port it back into the real codebase with much more confidence.

In this post, we’ll walk through what that playset looks like, how to build it, and how to use it to de-risk your next refactor.

Architecture as a Set of Viewpoints

In architecture (both physical and software), there isn’t just one “true” diagram. Instead, you use multiple diagrams that each highlight a different concern:

• Static structure: how components, modules, and data structures relate.
• Dynamic behavior: how requests, events, and data flow through the system over time.

An architectural model in software is made up of several views:

• A logical view for developers (modules, layers, domains)
• A process or runtime view (services, threads, queues, workflows)
• A deployment view (servers, containers, regions)
• A data view (schemas, key entities, data ownership)

Each view is a different viewpoint, tailored to a particular scope of analysis or stakeholder concern. For example:

• Backend devs may care about how domain modules depend on each other.
• Ops or SREs may care about service boundaries and call graphs.
• Product and UX may care about end-to-end flows and where latency or failure can occur.

Your refactor will almost always affect more than one of these views. That’s why a single diagram, or just “looking at the code,” is not enough.

The Analog Refactor Playset is about quickly constructing these views in a light, flexible way so you can try design ideas before code changes make them expensive.

The Analogy: Toy Models Before Real Construction

Physical architects rarely start by rearranging steel beams on the building site. They start with scale models and plans:

• Cardboard buildings on a table
• 3D-printed components
• Sketches of load paths, ventilation, and utilities

These models are cheap, reversible, and explorable. You can move a wall, spin the model, or scribble over a floor plan in seconds.

Building a “toy model” of your codebase is the software equivalent:

• You sketch components on a whiteboard.
• You lay out modules or services as sticky notes.
• You draw sequence diagrams of critical flows.
• You even spin up small, synthetic code projects that mimic the structure you want.

None of this touches the existing production code. It’s a safe sandbox where you can:

• Explore different boundaries and abstractions
• Visualize dependencies and hotspots
• Play with designs for new modules or services
• See how data and behavior flow in the new world

Only once that toy model makes sense do you systematically move changes into the real system.

Refactoring as Design, Not Just Cleanup

Refactoring is often treated as “tidying up code.” But that’s too small a frame.

Refactoring is the disciplined process of improving the internal design of existing code without changing its external behavior.

Martin Fowler’s book, Refactoring: Improving the Design of Existing Code, is the classic reference here. It documents concrete refactoring techniques like:

• Extract Method / Extract Class
• Introduce Parameter Object
• Replace Inheritance with Delegation
• Move Method / Move Field
• Encapsulate Collection

These are small, mechanical moves you can chain together. But what guides which moves you make? That’s where your architectural model and toy system come in.

When you treat refactoring as a modeling and design activity:

• You start with what the architecture should look like.
• You identify migration paths from current state to target state.
• You plan sequences of small refactorings to realize that design.

Instead of “I’ll just start cleaning up and see where it goes,” you have:

“Here’s the target architecture. Here are the modules/services we need. Here are the major dependencies we must break. Here is the order in which we’ll do it.”

The Analog Refactor Playset is the set of tools and practices you use to design that target state and migration path.

What’s in the Analog Refactor Playset?

You don’t need fancy tools. The playset is deliberately low-tech, tactile, and easy to change.

Core components:

1. Static structure map

   • Boxes and arrows (on a whiteboard, paper, or digital board) showing
     • Modules, services, or layers
     • Key dependencies between them
   • Mark hotspots: places with high churn, high defects, or high coupling.

2. Dynamic behavior diagrams

   • A handful of sequence diagrams or flow diagrams for your
     • Most critical use cases
     • Most fragile flows
     • Most performance-sensitive paths

3. Responsibility / ownership notes

   • Who owns which module or component?
   • Where are domain concepts scattered?
   • Where are data and behavior mixed in confusing ways?

4. Experiment space

   • Sticky notes or index cards you can move around to represent
     • Potential new modules or services
     • New boundaries between domains
     • Alternative call patterns between components

5. (Optional) Toy code project

   • A tiny repo (or package) that implements just the shape of your new architecture
   • Fake interfaces, stubbed methods, and minimal logic
   • Used to try out new abstractions and package structures without the weight of the real code

The key is that every piece is easy to move, erase, or throw away. That freedom to change encourages exploration.

How to Build a Toy Model of Your Codebase

You can create your Analog Refactor Playset for a specific refactor in a few steps.

1. Capture the Existing Structure (Roughly)

Don’t start in the IDE. Start on the desk.

• Draw your services or main modules as boxes.
• Connect them with arrows showing who calls whom.
• Annotate with:
  • “Too many responsibilities”
  • “Knows too much about X”
  • “Hard to test”

The goal is clarity, not precision. You’re looking for:

• Cycles
• God objects or god services
• Layers that leak abstractions

2. Map a Few Critical Flows

Pick 2–4 essential flows:

• Signup / login
• Checkout
• Data ingestion pipeline
• Report generation

For each, draw a quick sequence diagram:

• Which components participate, in what order?
• Where are the conditionals or branching paths?
• Where is data transformed or validated?

These dynamic views will show where behavior crosses awkward boundaries.

3. Propose a Target Architecture on Paper

Now, with sticky notes or boxes:

• Group related responsibilities into candidate modules.
• Move logic closer to the data it owns.
• Separate concerns (e.g., domain logic vs. infrastructure).
• Consider new boundaries (e.g., split a service in two, or merge two that are inseparable).

Don’t worry yet about how to get there—just design something that:

• Has clearer responsibility
• Reduces unnecessary coupling
• Makes important flows more direct

4. Walk the Flows Through the New Design

Take your earlier sequence diagrams and re-enact them through the new structure:

• Does the flow become simpler or more complex?
• Are you introducing too much indirection?
• Do new boundaries create awkward cross-calls or circular logic?

Adjust the model until the flows feel cleaner and more explicit than they were.

5. Derive a Refactoring Plan from the Model

Now, turn your model into a sequence of concrete refactorings, using techniques (and names) from Fowler’s Refactoring as your building blocks.

For example:

1. Extract core domain logic from OrderService into OrderDomain class.
2. Introduce interfaces between OrderDomain and payment infrastructure.
3. Move payment-related methods from OrderService into PaymentGatewayAdapter.
4. Update callers to go through the new abstractions.
5. Delete old, now-dead paths.

Your toy model tells you:

• What needs to exist
• Which dependencies must be cut
• Which abstractions you need to introduce

The plan is then implemented as a series of small, behavior-preserving refactors.

Why This Makes Large Refactors Less Risky

Creating a small, manipulable representation of your architecture before you start changing code has several benefits:

• Clarified dependencies and hotspots
  You see where complexity and coupling really live, instead of discovering them mid-refactor.

• Cheaper mistakes
  It’s far easier to rearrange sticky notes than to unwind half-merged code.

• Shared mental model
  The whole team can stand around the same diagrams, debate options, and converge on a design.

• Disciplined execution
  Once the architecture and migration path are clear, you can apply small, well-known refactorings with confidence.

• Better abstractions
  When you treat refactoring as design, you focus on domain boundaries, ownership, and long-term maintainability—not just “cleaner code.”

This doesn’t replace tests, code review, or gradual rollout. Instead, it complements them by ensuring you’re changing toward a coherent design, not just rearranging code.

Bringing It Into Your Next Refactor

On your next sizable refactor, try this:

1. Block 1–2 hours with the team before touching any code.
2. Draw the current architecture and 2–3 critical flows.
3. Propose alternative structures with sticky notes and diagrams.
4. Walk the flows through the new model and refine it.
5. Write down a step-by-step refactoring plan driven by that model.
6. Only then open the IDE and start executing the plan.

You’ll still need discipline, tests, and review—but the work will feel much more guided.

Conclusion

Refactoring isn’t just about making code look nicer; it’s about improving the internal design of a living system without changing its external behavior. To do that well, you need more than ad-hoc edits inside the editor.

The Analog Refactor Playset invites you to:

• Build toy models of your architecture with simple diagrams and sketches.
• Use multiple viewpoints—static and dynamic—to understand structure and behavior.
• Treat refactoring as design work first, code work second.

By the time you touch production code, your biggest design decisions will already have been made—safely, on the desk, where experimenting is cheap and reversible. That’s how you make big changes feel a lot less risky, and end up with systems that are cleaner, clearer, and easier to evolve.