Gordon Walters Koru Patterns in Processing

Posted Oct 24, 2013

Gordon Walters was an artist and graphic designer, born in Wellington, New Zealand in 1951. Though he produced works in a variety of styles, he is best known for his koru series of prints, which are instantly recognisable to most New Zealanders. One of his most celebrated pieces, Maheno, is fairly typical of the series as a whole:

Gordon Walters - Maheno
Gordon Walters - Maheno

The artworks take their name from the koru, a spiral pattern representing the tight curl of a new fern frond. It is one of the primary motifs of Māori art, particularly wood carving, and symbolises creation, life, and new growth. I think Walters’ modern abstraction of this traditional pattern retains the symbolism, but it seems that the artist didn’t see it that way himself. In this article in Art New Zealand, Walters is quoted:

My work is an investigation of positive/negative relationships within a deliberately limited range of forms; the forms I use have no descriptive value in themselves and are used solely to demonstrate relations. I believe that dynamic relations are most clearly expressed by the repetition of a few simple elements.

Ultimately though, I like these prints not because of any implied meaning, but simply because they’re such striking images, and because they’re fun to look at. I like the way the black background of each white koru becomes the foreground of a black koru as you scan across. It’s obvious, but still seems to trick the eye, kind of like a Blivet. I am also reminded of M. C. Escher’s Sky and Water I, an interlocking grid of fish and flying birds, where the negative space around the birds forms the images of the fish, and vice versa.

Looking at Walters’ work, I couldn’t help but wonder how he made them. I’d always assumed they were screen prints, and some of them are, but many more still are painted directly on the canvas. He must have had a steady hand. I do not have a steady hand, but I do know a little Processing, so I thought it might be a fun exercise to randomly generate koru patterns in Walters’ style.

I feel like the way I approached the problem was almost cheating, but it works, and I’m quite pleased with the results. Basically I start by filling the canvas with alternating light and dark bars, then step through each bar adding the round koru forms. By adding the koru forms, the current bar is broken and the previous and following bars of the alternate colour are joined. Chosen purely at random, koru (koru? korus? korae? What is the plural anyway?) can overlap with those on the previous line. To avoid this, I used a simple mechanism to find the usable range in each bar and then selecting a position randomly inside that range.

This basic process resulted in images that were a reasonable likeness of Walters’ but there were features in some of his art that I wanted to capture as well. First of all, every so often two koru will be separated by a small circle. Drawing the circle is simple enough, and it required just a small update to the positioning algorithm to account for the longer patterns. Next, I wanted some bars to have multiple koru, breaking a line in several places. Fixed probabilities determine whether there will be zero, one, or more koru on a line, and whether any given koru pair will include a circle between them.

Here are some sample images.

Koru 1
Koru 2
Koru 3
Blue & Yellow
Koru 4
Sky Blue

As my first real Processing project I’m quite pleased with results, even if the code is a bit fugly. I would quite like to rewrite it in Processing.js at some point so it will run in a web browser without requiring Java. It would also be fun to animate it, as a left-right infinite scroll sort of thing, or more interactively, such that the koru avoid or are attracted to the mouse pointer.

If you’d like to take a look at the code, it’s available on GitHub here.