DRAKULA stands for Drachenkurven, überlagert (dragon curves, overlaid). The dragon curve is a fractal object. The basic idea was first investigated by NASA physicists John Heighway, Bruce Banks, and William Harter, and described by Martin Gardner in his 1967 column Mathematical Games in the Scientific American. However, the mathematical theory for it was not developed until 1970 by mathematician Chandler Davis and computer scientist Donald Knuth. In the same year, Franke began to use it for his computer art work.
Dragon curves emerge from sequences of left and right turns according to certain rules. The program allows to string together and superimpose dragon curves of different order–or even sections of such curves. Left and right turns were not only represented in the usual way by right-angled bends, but by mathematically defined elements, triangles or multiple bent curve sections. These elements were designed in such a way that when they are overlaid, clearly recognizable new form elements are created by overlaps and appositions. The overlay of closed curves in different colors is particularly appealing. The dragon curves were also interesting to Franke as an object of experimental aesthetics and for his studies on the psychology of information, since here the rare case of an easy way to indicate their statistical information (complexity) occurs; this is equal to the number of 0.1 indications used to construct them. Franke also superimposed dragon curves–mostly mirrored–with each other and used not only straight lines as single elements, but also employed other shapes, for example semicircles or triangles, as basic elements.
The picture series of DRAKULA was created with a Siemens System 4004, the Fortran program was written by Peter Henne from the Gesellschaft für Datenverarbeitung GMD according to detailed specifications by Franke. The plots were realized by Peter Vordermaier at Siemens AG.