0. What Is a Chart, Really?
No code yet. This is the part that doesn’t change with the tool.
0.1 — How do you show “more”?
You have two apples on the table and your friend has five. How do you show who has more, without saying the numbers out loud?
Answer
Line the apples up in two rows and let me look. Whoever’s row is longer has more.
🍎🍎
🍎🍎🍎🍎🍎
0.2 — What did you just use to show “more”?
That’s already a chart. What did you just use to show “more” — your voice, or something I could see?
Answer
Something I could see: length.
0.3 — What else can stand for a number?
Length was standing in for a number. What else, besides length, could show “more”? Think of anything that can grow or shrink without adding more apples.
Answer
Size of a circle. Darkness of a color. How high something is drawn. How far right it sits.
0.4 — What are these things actually doing?
That’s the whole list, more or less: position, length, size, darkness, angle, color.
Every chart uses one or more of these to stand in for a number.
If I drew two circles and two bars with the same two numbers, which pair would you compare faster and more correctly?
Answer
The bars — I can just look at where the top of each one lands.
0.5 — Why is position so powerful?
Right. Position is what your eye is best at.
Circles (size) and pie slices (angle) are things your eye actually gets wrong more often. Try guessing which of two circles is twice the area of the other, and you’ll usually underguess it.
So why does anyone still use pie charts and bubble sizes at all, if position is so much more accurate?
Answer
Maybe because it looks nicer? Or because sometimes you don’t want to compare exactly — you want to feel like a whole thing is being split into parts.
0.6 — Is accuracy always the goal?
Exactly.
Sometimes the question isn’t “Which is bigger?” It’s “Does this feel like a whole made of parts?”
The chart type is chosen by the question, not by which one is prettiest.
You already had the apples lined up in two rows before we called it a chart. What did turning it into a chart actually add, if the answer was already sitting right there in the two piles?
Answer
Speed, maybe? I didn’t have to count them one by one.
0.7 — What can make a chart dishonest?
That’s the entire reason charts exist:
trading exact numbers for instant comparison.
A table never lies to you — a chart can, if it’s badly drawn.
If I drew your two apples as circles, but made my circle look 3 times bigger than yours even though I only had 2.5 times as many, what would you call that?
Answer
A lie. Even if you didn’t say a wrong number out loud.
0.8 — What should you ask before choosing a chart?
That’s visual honesty: the size on the page has to match the size of the truth underneath it.
Last question.
I hand you a pile of numbers and ask you to chart it. Before you pick pie, bar, line, or anything else — what’s the first thing you now know to ask yourself?
Answer
What am I trying to show — “which is biggest,” or “how big is the whole,” or something else? The answer decides which one I draw.
The Principle
Everything from here on — bar, pie, line, heatmap, word cloud — is this same eight-step dialogue applied to a different shape.
The code changes.
§0 doesn’t.