teaching machines

Annotations in Twoville

Software for creating digital media tends to be driven by a mouse or stylus. The user directly manipulates shapes until they feel right. Twoville and Madeup, on the other hand, are programming interfaces for digital media. While code opens the door to algorithmic generation, programming interfaces tend not to give as much feedback as direct […]


Twoville got support for arcs a couple of months ago. Full SVG supports elliptical arcs, but I don’t think they’re very intuitive and their parameters should not face the user. I restricted Twoville to circular arcs and exposed friendlier parameters. In my original draft, the programmer specified an arc via its starting point (which is […]

University of Canterbury Seminar

Hi, I’m Chris and I teach people to teach machines. But I am a reluctant computer scientist. Sometimes I get concerned that the thing I know the most about is not directly linked to my survival. My father knew how to keep machines running. My wife grows vegetables. In a post-apocalyptic world, they would be […]


Twoville serves two purposes: to create SVG images that can be used as input to laser and vinyl cutters to create animations To support the second of these, I have been using time blocks to define geometric properties at particular keyframes, and then letting the animation system interpolate between the keyframes. Like this: Here we […]

Polar Graph

A year ago I decided to see if fifth graders could create shapes using polar coordinates. I bet myself that they could if we spent some time first traversing a polar grid, identifying the labels of the rings and the spokes. We didn’t think of them as angles and radii, because those semantics weren’t important […]

Phone Programming

Twoville now supports masking, which means we can subtract shapes from other shapes. Since I’m teaching a course on mobile app programming this semester, phones have been on my mind. Accordingly, here’s one of the first runs of the masking feature: In this code, hole is a container of other shapes that will be subtracted […]


A year ago some students and I started designing programming languages for generating 2D vector art. I called my language Twoville, which pays homage to Seymour Papert’s metaphor of learning math in Mathland just as we learn French in France. The language is a place to learn about and forge 2D shapes. After the semester […]

Multiple Assignment in Twoville

As I dream up animations in Twoville, I find myself generating a lot of shapes that share properties with other shapes. For instance, these two circles have the same radius and color: a = circle() b = circle() a.radius = 10 b.radius = 10 a.rgb = [1, 1, 0] b.rgb = [1, 1, 0] I […]

With Blocks in Twoville

In my software engineering class in college, Dr. Drake dropped on us a half-written piece of software that managed a database of movies. Our challenge was to improve it. It was the first and only time I’ve touched Visual Basic, and I remember only one thing about the project and the language: with-statements. Suppose you’re […]

Twoville Inching Along

Thanks to a snow day yesterday, I can now export animated GIFs from Twoville, my 2D drawing language. Gif.js made this possible. However, Jeremy, I think naming your project with .js suffix was a big mistake. When one clones the project, one ends up with a directory with a .js extension, which messes everything up. […]