Byrne's Euclid

What Byrne's Euclid actually is

Nicholas Rougeux rebuilt Oliver Byrne's coloured edition of Euclid's Elements as a website, keeping the original conceit: proofs use coloured shapes in place of letters such as ABC. Diagrams are redrawn as scalable vectors and set alongside the proofs they belong to.

Why it is worth your time

Byrne's colour trick means you follow a proof by matching a red line to a red line, and it works well enough that an 1847 idea still beats modern notation.

Common questions

Is Byrne's Euclid free?

Yes. Byrne's Euclid is free and does not ask you to register or hand over an email address before you can use it.

How long does Byrne's Euclid take?

Five to fifteen minutes of proper attention. We file it under "Coffee break" — an 1847 geometry book where colour replaces the labels.

Does Byrne's Euclid work on a phone?

Yes. Byrne's Euclid works on a phone as well as it does on a laptop.

What kind of site is Byrne's Euclid?

We list it under Explain Everything — hard things, made suddenly obvious. Byrne's colour trick means you follow a proof by matching a red line to a red line, and it works well enough that an 1847 idea still beats modern notation.