Episode 1 · Prologue — Code Is Architecture: Into the Screen

It's a clear afternoon, one day in October, and I'm sitting in front of my computer, writing. A photo I saved last October sends me a notification, as if curious about who I am now. I double-clicked the folder icon labeled "Photos." In that instant, it's as if a door opened on the screen. The moment I stepped through it, photos holding memories from last October spread across the walls of a hideout room we call a folder. The materials and objects inside that hideout room are what we call files. On the shabby walls of that hideout hang photos of memories with family, and on the shelf where I was working back then, I can see documents stacked neatly. But looking again, there are several more doors in this room. These are subfolders. Each subfolder is a small room split off from the main folder. In other words, inside this big, wide house called a computer, we place files into various folders and, when we need them, open the doors one by one, step inside, and recall our memories. It may sound clever, but the folder icon clearly hints that it is both a container you can put things into and a room. It's not so different from the way we already think. In our everyday digital lives, without even realizing it, we are strolling through these virtual spaces, these virtual homes.

Rather than lingering in this first hideout-room folder, let's look around more thoroughly. Just like a real house, in a computer everything occupies its own place. On a wall that would feel bare if empty hang family photos; in another corner are photos from last year's vacation. And on the desk sit, neatly arranged, the materials I was working on last year. This simple act of opening a folder gives the feeling of entering a part of my own house, one built not of brick and concrete but of code and components. Consider this: the structure we call software can be not merely something you use, but a space you can move through and inhabit. My hope is that this structure feels never cold, but rather warm and cozy.

Now let's expand further and look at another everyday scenario. In the hideout room, I noticed an old photo hanging upside down. So I tried to turn it the right way up. But the photo is nailed firmly to the wall. There is, however, a lever off to the side. I pulled it. And the photo rotates back to its original orientation. In other words, some device built into the house, triggered by clicking the lever, the "rotate" button, flipped the photo. It's as if clicking that rotate button were pulling a lever on the computer's (the house's) control panel in a secret room. Behind it, gears begin to turn (code executes), electricity flows through circuits (data moves through pipelines), and all sorts of vigorous activity begins. In an instant, the machinery of the software comes alive and realigns the photo. The button the user pressed can also be seen as similar to a light switch on the wall of a house. You can flip it easily, but it operates connected to the entire electrical system hidden behind the button. This everyday action hints that behind what we see on the screen lies a structured world. At this stage, we won't try to understand that whole system. But if a computer program feels to you like the wiring of a building hidden behind a button, then you understand it very well indeed.

As you make clicks like these, adjusting the brightness with a light switch, or opening a door to enter another room called a folder, you begin to sense a basic order. Every task you perform in software has a place where that work gets done, just like dedicated rooms for different purposes: a living room, a kitchen, a bedroom. Just as in a well-designed house the kitchen is a space for cooking and the bedroom a space for sleeping, software too has various modules or sections that handle specific tasks (loading, editing, saving an image). These modules aren't directly visible, but we can experience their arrangement indirectly. The fact that finding or editing a photo has become intuitively easy is not magic; it's thanks to excellent architecture. Like a well-ordered house or city, the design of software quietly guides the user toward the experience they want.

Opening a folder as if entering a room; clicking a button as if operating a hidden control panel; through simple scenes like these, we can connect the familiar physical world with the invisible world of code. This first step should be light and vivid. By grounding abstract programming ideas in concrete experience, we are literally opening a door that anyone can walk through. For example, if you've ever browsed a website or organized your files, you already have an intuition for these metaphors. Think of a website's various menus as a city's road signs, guiding you from one district (page) to another district (page). Or think of the home screen where your smartphone's many apps are laid out as a private apartment, where each app is a room with its own distinct purpose. The advantage of such analogies is that they let you feel the digital world as something real and familiar.

This episode won't explain everything at once. Just as touring a grand mansion begins with looking around the lobby, let's start with a few accessible rooms in the enormous mansion called "code as architecture." The goal of this chapter is not to walk down every corridor and describe every structure in detail, but to spark curiosity. What lies hidden behind other icons and apps? Beyond these simple examples, how are code and architecture one and the same? These questions are precisely the curiosity we truly want to provoke.

We stand at this captivating, fascinating starting point. A path has opened for us to explore more deeply. In the next episode (Episode 2), we'll set off on a journey beyond this first room and control panel, into the grand design of software itself. And beyond that, we'll examine the entire digital city and the code of its towering skyscrapers. We'll look at how directories (folders) become neighborhoods, how software components interconnect like buildings and bridges, and even how the latest technologies, such as AI language models, exist within an endlessly expanding cityscape and have become modular, transformable structures. But don't worry. As we make our way, step by step, down the streets and through the corridors, the structure of digital civilization will come into full view before you know it.

For now, take a moment to appreciate the simple clicks and taps you make every day. Behind them lies a structured world, built by the many developers who labored for your exploration. Code is architecture, and you have just passed through the front door.