Whence: How Inventions Connect

Khang Azun

About this app

Whence is a map of how human inventions depend on one another. Take one away and see what goes dark. Pick any two and find, or solve, the line that joins them. Every link says why.

TAKE IT AWAY
What if the battery had never been invented? Pick any invention, guess how much of the map depends on it, then watch everything that needed it go dark on the tree, link by link. Without the battery, 47 of the 162 inventions in this map go with it. See the farthest echoes, the long chains that tie it to inventions centuries later, and compare two inventions to see which leaves the bigger gap.

FROM ONE TO ANOTHER
How did fire lead to the smartphone? Choose any two inventions and solve it: start from the older one and pick, step by step, what it led to on the way to the newer one. Every right pick shows its reason; dead ends are marked. Or just show the answer, with a plain sentence for every step, and draw the line on the tree.

SHARE A CARD
Turn a challenge, an answer or a world without one invention into a picture for a story or a post, made on your phone. "Can you connect fire to the smartphone?" hides the answer for a friend to find.

162 INVENTIONS, 310 LINKS, EACH WITH ITS REASON
From the Stone Age to the connected world, in eleven eras. A link means the newer invention could not have been made without the older one: the light bulb needed glassblowing because the filament has to sit inside a sealed glass globe. Every page names its sources, and How this map was made explains the method.

THE WHOLE TREE ON ONE MAP
See all 162 inventions laid out by era. Pinch to zoom, tap any one and its whole history lights up: everything that came before it and everything it led to.

A ROAD EVERY DAY
Today's road starts from one invention and walks back in time. At each step, pick what it could not exist without from six choices. Wrong picks cost stars. Everyone gets the same road each day, and a new one comes tomorrow.

WHICH CAME FIRST?
Ten pairs, from easy to close: the printing press or the compass? The battery or the domesticated dog? Then see both dates.

THE SOUND OF EACH ERA
A quiet background follows you through time, made entirely in the app, from wind and a crackling fire in the Stone Age to a computer fan in the 1980s. Turn it off any time.

PRIVATE BY DESIGN
No account, no ads, no analytics, no tracking. Everything is in the app and it works without a network. Your progress stays on your device.

Requires Android 8.0 or later.

What’s new

New in 1.1:
• Take it away: pick an invention, guess how much depends on it, and watch everything that needed it go dark on the tree.
• From one to another: choose any two inventions and solve the line between them step by step, or show the answer with a reason for every step.
• Share a card: turn a challenge, an answer or a world without one invention into a picture.
• Sources on every page, and How this map was made in Settings.