One night, watching Black Mirror on Netflix, a thought struck me.
ever look at the same screen?”
Designers think in Figma. Layers, components, alignment.
Engineers think in the terminal. Commands, output, structure.
Two modes of thought, each living on its own tool.
I had a feeling there were ideas falling into the gap between them.
The series Black Mirror interrogates the relationship between technology and people.
What is reflected on the far side of the screen is yourself.
When you draw something, what appears on screen is thought itself.
So I named it Black Mirror Board.
The name means “black mirror.”
What a black mirror usually shows is an uneasy future.
But when you look into this board——
a green smile grins right back at you.
So the least I could do was make it smile.
The logo is a plain green smile.
Green is the color of life. The color of Lake Biwa. The color of warmth.
The coldness of technology the name warns about,
the mark quietly refuses. A tool is allowed to smile.
What I obsessed over in the design was simplicity.
No framework. No library. One HTML file. Runs in the browser alone.
Why? Anything extra makes thinking heavier.
A tool should be light. As close to a blank page as possible.
Shapes drawn on the canvas
answer to terminal commands.
Type a command, and the canvas moves.
Drawing and driving happen in the same place.
The designer never has to write code.
The engineer never has to open a design tool.
The two look at the same canvas and speak the same language.
That, to me, is magic.
Drawing (a designer’s intuition) and typing (a hacker’s command).
The two meet on one and the same black mirror.
Type $sakura into a text box, and cherry blossoms drift across.
Paste JSON, and a new spell is added.
Tell an AI “I want it to move like this,” and it hands back JSON that runs.
Without writing code, the canvas expands without limit.
In the end, what does this make lighter for you?
Cutting a feature is ten times harder than adding one. Keep giving in to “maybe I need this too,” and the file quietly bloats. 499KB is the result of cutting.
The rule of “everything in one file”
trained the habit of never bringing in a dependency.
A sensitivity to runtime cost, a deeper grasp of browser APIs——
all of it came from this constraint.
By Lake Biwa, I kept building it while using it every day.
v1.3 added a GIF canvas, alignment, templates, palettes and auto-theming.
More features — but the philosophy has not changed.
Zero dependencies. One HTML file. Runs in the browser alone.
It launched on Product Hunt. It reached designers and engineers around the world.
“I’ve been waiting for a tool like this” — those words were the best reward.
From Shiga, through a single browser, to the world.
