Multi-scale camouflage is a type of military camouflage combining patterns at two or more scales, often (though not necessarily) with a digital camouflage pattern created with computer assistance. The function is to provide camouflage over a range of distances, or equivalently over a range of scales (scale-invariant camouflage), in the manner of fractals, so some approaches are called fractal camouflage. Not all multiscale patterns are composed of rectangular pixels, even if they were designed using a computer. Further, not all pixellated patterns work at different scales, so being pixellated or digital does not of itself guarantee improved performance. The first standardized pattern to be issued was the single-scale Italian telo mimetico. The root of the modern multi-scale camouflage patterns can be traced back to 1930s experiments in Europe for the German and Soviet armies. This was followed by the Canadian development of the Canadian Disruptive Pattern (CADPAT), first issued in 2002, and then with US work which created the Marine pattern (MARPAT), launched between 2002 and 2004. Principle Scale invariance The scale of camouflage patterns is related to their function. Large structures need larger patterns than individual soldiers to disrupt their shape. At the same time, large patterns are more effective from afar, while small scale patterns work better up close. Traditional single scale patterns work well in their optimal range from the observer, but an observer at other distances will not see the pattern optimally. Nature itself is very often fractal, where plants and rock formations exhibit similar patterns across several magnitudes of scale. The idea behind multi-scale patterns is both to mimic the self-similarity of nature, and also to offer scale invariant or so-called fractal camouflage. Animals such as the flounder have the ability to adapt their camouflage patterns to suit the background, and they do so extremely effectively, selecting patterns that match the spatial scales of the current background. Design trade-offs When a pattern is called digital, this most often means that it is visibly composed of computer-generated pixels. The term is sometimes also used of computer generated patterns like the non-pixellated MultiCam and the Italian fractal Vegetato pattern. Neither pixellation nor digitization contribute to the camouflaging effect. The pixellated style, however, simplifies design and eases printing on fabric, compared to traditional patterns. While digital patterns are becoming widespread, critics maintain that the pixellated look is a question of fashion rather than function. The design process involves