Joel Gethin Lewis

Lecture 2: Drawing

- Moving from one dimension to two.
- x,y co-ordinates, area, Pythagoras' theorem.
- Circles, Sine, Cosine and Pi.
- Two dimensional lists (or arrays) for remembering pixels.
- Delaunay triangulation / Voronoi diagram.
- Bonus: Art from Rules.

- Going from a line to a square.
- Artwork: Flatland by Edwin Abbott Abbott.

- (x,y) pairs are Cartesian co-ordinates in Euclidean space.
- Y on computers is the opposite way to the way you learnt in school - because old computers scanned from the top down using Cathode Ray Tubes.
- Area - if you double the width and the height, area scales x4 NOT x2.
- Pythagoras' theorem - see proofs on Wikipedia page and Better Explained. P.S. Better Explained is AWESOME!

- What is a circle? "It is the set of all points in a plane that are at a given distance from a given point".
- A Gentle Introduction To Learning Calculus from Better Explained.
- Intuitive Understanding of Sine Waves.
- Sine and cosine and tan aka Trigonometry again, from Better Explained.

- 2D arrays, or arrays of arrays.
- Artwork: Every Icon (1997) John F. Simon, Jr.
- Question, how might you store a two dimensional array within a one dimensional one?

- The Voronoi diagram is the diagram of boundaries between a set of points such that within the boundaries, one is closer to that point than any other.
- The Delaunay triangulation is the diagram of triangles of the Voronoi diagram such that no triangle is within another.
- The Voronoi diagram interactively.
- Artwork: Boundary Functions by Scott Snibbe, who now works for Facebook.

- My favourite is Agnes Martin. The Tate Modern on Agnes Martin (great quote!) .
- Sol LeWitt was a pioneer in minimalist and conceptual art, drawing up rules or algorithms that then could be carried out by anyone - "The system is the work of art; the visual work of art is the proof of the system"
- History of Design Systems by Rune Madsen has a series of references on Sol LeWitt and others.
- Great recent article on Generative Art by Jason Bailey.
- Solving Sol, Javascript implementations of his works.

- More about me: @joelgethinlewis
- Get in contact via: www.joelgethinlewis.com
- Website:

https://jgl.github.io/ComputationalThinking2018 - Today's slides:

https://jgl.github.io/ComputationalThinking2018/lecture2.html