In the catalogue of a 2010 retrospective of Karl Kvaran's work at the National Gallery of Iceland, Ásdís Ólafsdóttir writes about the artist's work in the early 1970s: “With a solo exhibition at the National Museum in November 1968 we see a marked difference in his art. In his gouache paintings, painted in the previous two years, delicate, angular lines, twisting about the coloured picture plane like stylized lightning, have replaced the thick vertical and horizontal framework; diagonal lines and irregular shapes appear instead of squares. … The next transformation in Karl's art appeared in his exhibition at the National Museum three years later. The he had introduced curved forms and increased the size of the coloured planes. In addition, the lines were not all as clearly drawn as before and some smudged in an almost organic way. … In November 1974 he held a large exhibition at the Nordic House where he displayed … large oil paintings where the object was either the rhythm of broken circles or large circular shapes composed of both delicate and powerful lines. … What distinguishes … Karl's oils after 1974 is that they are painted in many layers, and older brushstrokes and lines can always be discerned under the surface. This tendency intensified with time and the paintings became more succinct in both form and colour.” (Ásdís Ólafsdóttir: Karl Kvaran, p. 18–19).
Reputation, and other paintings in a similar vein, were made in the following years. Ásdís Ólafsdóttir writes: “after 1973–1974 [Karl] painted a series depicting organic wave forms in which colour and line go together. These pieces are related to a certain extent to Þorvaldur Skúlason's paintings of troughs and peaks, except that Karl's lines are much softer and circular, while Þorvaldur's forms all tend in one direction, out of the picture plane.” (Ásdís Ólafsdóttir: ibid., p. 20).