When the ‘artist’ on the train is actually sketching microservice boxes

Level 1: Not That Kind of Drawing

A woman on a train sees a handsome stranger sketching away in a notebook and her imagination takes off: he must be an artist, and maybe — maybe — he's drawing her, like a scene from a movie. She's already blushing. Then we see the notebook: it's full of boxes and arrows, like a seating chart for a school, planning how a computer should keep track of students and their classes. It's funny the way it's funny when you wave at someone who was waving at the person behind you — a big romantic balloon popped by something completely, perfectly boring. He's not dreaming about her at all. He's dreaming about spreadsheets.

Level 2: Boxes, Lines, and What They Mean

An entity-relationship diagram (ERD) is a blueprint for a database, drawn before any code exists:

• Entities (the boxes) are the "things" you store: Student, Course, Seminar. Each becomes a table.
• Attributes are facts about an entity: a student's name, a seminar's term ("Fall", "Spring").
• Relationships (the connecting lines) say how things relate: a student enrolls in many seminars; a seminar belongs to one course.

CREATE TABLE student  (id INT PRIMARY KEY, name TEXT);
CREATE TABLE course   (id INT PRIMARY KEY, title TEXT);
CREATE TABLE seminar  (id INT PRIMARY KEY, course_id INT REFERENCES course(id), term TEXT);
CREATE TABLE enrollment (student_id INT REFERENCES student(id),
                         seminar_id INT REFERENCES seminar(id));

That last table is the punchline of every first database course: students take many seminars and seminars hold many students, so you need a junction table — something nearly every junior tries to avoid once, by jamming a comma-separated list into a column, before learning why that's a war crime. The notebook in the comic is essentially the homework — or work assignment — version of this exact problem, sketched the way most schemas actually begin: on paper, with arrows, long before a CREATE TABLE is typed. ERDs are cousins of UML diagrams, the broader family of boxes-and-lines drawings engineers use to think before they build.

Level 3: Third Normal Form, Zero Romantic Form

The comic runs a textbook romance-subversion arc — "OOO! AN ARTIST!", then "IS HE DRAWING ME??" — and detonates it in panel four with the least romantic artifact a notebook can contain: an entity-relationship diagram. The sketched boxes are labeled with Student entities, a Course ("Languages Intro to Computer Science"), and Seminar instances tagged "Fall" and "Spring," all wired together with relationship lines. He is drawing, technically. He's drawing a many-to-many enrollment relationship on his commute.

What makes this land for working engineers is how true the underlying behavior is. Data modeling is exactly the kind of problem that colonizes idle time. Unlike writing code, an ER sketch needs no laptop, no IDE, no Wi-Fi — just paper and an unresolved question like "is a Seminar an entity or just an attribute of Course offering?" That question will ride the subway with you whether you invited it or not. The comic's fourth panel is what whiteboard brain looks like from the outside: the engineer has mentally left the train entirely and is somewhere deciding whether Seminar needs its own primary key or can live as a weak entity hanging off Course.

There's also a sharper observation about perception of creative work. The woman's fantasy depends on a cultural hierarchy where sketching = art = soulful, while diagramming = engineering = sterile. But schema design is genuinely a creative act with taste, trade-offs, and aesthetics — a clean model that survives requirement changes is closer to good architecture than to bookkeeping. The classic student–course–seminar domain he's sketching is the canonical teaching example precisely because it's deceptively hard: enrollment is many-to-many, offerings vary by term (hence the "Fall"/"Spring" annotations), prerequisites form a graph, and every naive first draft eventually gets dismantled by normalization. Somebody who voluntarily does this on public transit has either a deadline or a genuine love of the craft. Possibly both; the deadline usually generates the love retroactively.

And the final cruelty: in the engineer's worldview, she could be in the notebook — as a row, not a portrait. Modeling people as entities is the day job. Capturing their likeness is somebody else's department.