Crafty, Geometry Joys, Math and Computer Science Everywhere, Murderous Maths, Simon teaching, Together with sis

Spherical Geometry

After Simon read up on spherical geometry on, he and Neva crafted some pretty colourful half-spheres. How’s that as an alternative to Easter eggs? Simon has also discovered a great tutorial on spherical geometry by Think Twice: Spherical Geometry: Deriving The Formula For The Area Of A Spherical Triangle. Think Twice is an awesome resource for animated math, helping to understand mathematical concepts intuitively through visualising them (accompanied by beautiful music that Simon sometimes just turns on simply to have some math and music beauty on the background).

They also had fun looking for shortest routes across the Atlantic applying their knowledge of geodesics.

Simon had already recorded a video about how to make such a sphere, see our earlier publication here.

Coding, Java, Murderous Maths, Simon's Own Code

Simon’s changes to Daniel Shiffman’s Spherical Geometry Coding Challenge

Simon talks about his changes to Daniel Shiffman’s Spherical Geometry Coding Challenge: He has rewritten the code in an object oriented manner. Later he also turned the sphere into an ellipsoid using three radii.

Object oriented (Simon’s idea):

Adding colour (Daniel’s feature):

Turning the sphere into ellipsoid (Simon’s idea):

Simon would also like to try this with a cylinder:


Simon wanted to share his code in a readme in GitHub but he didn’t manage to create one within the specific (Sphere Geometry) project. Here is a screenshot of him sharing the code in Slack chat (for Coding Train fans):

Spherical Geometry sharing in Slack 29 Jun 2017

Coding, Geometry Joys, Milestones, Murderous Maths, Physics

Spherical Geometry Coding Challenge

Simon completed the Spherical Geometry Coding Challenge by Daniel Shiffman! In this challenge, he created a sphere in Processing (Java) using spherical coordinates and triangle strips. Simon had already tried doing this challenge before but back then he got stuck with the triangle strips.

He had to work with converting Polar coordinates to Cartesian, which basically means converting from radius r and angle θ to the x and y, which Java can understand. Simon intervenes to type this:

x = r * cos(θ)

y = r * sin(θ)

Here is Simon explaining Polar to Cartesian conversion to Dad last night:

SOHCAHTOA 14 Mar 2017

The screenshot above come from another video by Daniel Shiffman, explaining Polar to Cartesian conversion.

Here is how Simon built his sphere step by step: