Saltire Software

Apps and eBooks

Nicomedes Conchoid Clock

Saltire Software offers a wide range of Apps and eBooks for your mobile devices.

All were created with Geometry Expressions.

Try it yourself and see what apps you could create.

Euclid's Proof of the Pythagorean Theorem

Interactive Euclid's Elements

Few books in history have affected the development of mathematical, scientific, and philosophical thought more than Euclid's Elements.

The propositions and figures in the first 4 books form the geometric core of the work. We have turned the 127 original black and white static figures into colorful, interactive apps that illustrate the propositions dynamically.

What translator Sir Thomas Heath calls "one of the noblest monuments of antiquity" is newly dressed for the 21st century.

Euclid's Proof of the Pythagorean Theorem

24 Whimsical Clocks: and the mathematics behind them

Each chapter in this eBook begins with a weird clock, and discusses the mathematics that turns up in its wake. Most, but not all, of the clocks describe curves, so much, but not all, of the mathematics involves the geometry of curves.

Striking interactive visual proofs of intriguing results will whet your appetite to explore this mathematics yourself.

This book will delight anybody with an interest in mathematics, regardless of how much or how little formal education they have in the subject.

common core nuggets cover

Common Core Nuggets

Teachers are searching through an overwhelming mountain of information labeled "Common Core" to find materials and activities that will be helpful in implementing the standards with their students.

This group of apps consists of simple, short, and focused interactive demonstrations and explorations that are designed to help students master the important concepts of a single standard.

Available here in iOS, Android, TI-NSpireTM, and Web editions.
electronic atlas

Electronic Atlas of the Four Bar Linkage

Our Electronic Atlas of the Four Bar Linkage for your iPad combines the ease of browsing of a physical book with the flexibility of a computer program.

All diagrams from our paper Atlas are present, but in interactive form. You can animate the diagram, you can change the lengths of the links and placement of the coupler point to examine intermediate forms.

Involute Clock

Temporal Distortion

A collection of 24 whimsical clocks illustrate various mathematical and engineering concepts, and are just plain fun to watch. From a digital clock based on an abacus, to an analog clock whose hands wind around a circle, these clocks will entertain and intrigue you.

Exercise your inner Salvador Dali by distorting your own clocks. Challenge your inner mathematician with a clock whose seconds tick away Euclid's proof of the Pythagorean Theorem. Wake your inner engineer with a clock whose hands are driven by four-bar linkages.


Virtual Trammel

Mathematics and harmless fun are blended in this virtual trammel app.

Archimedes' trammel is a device for drawing an ellipse. Also known as the do-nothing machine or the nothing grinder, you can buy one made from wood at your local craft fair for a few bucks.

This app is a virtual trammel — you can grind away at nothing electronically. You can also investigate some of the interesting mathematics involved with Archimedes' beautiful mechanism.

Euclid's Muse

Euclid's Muse

Euclid's Muse is our website with hundreds of free interactive mathematical apps. The apps run in your browser on your computer, tablet or smart phone.

Geometry Expressions users can post their own apps to Euclid's Muse.