Long description

The figure shows a graph with two axes, labelled x position and y position. Each axis is marked at regular intervals, so that a regular grid of squares is defined that covers the entire graph.

The contents of each grid square are the pixels in the image. These pixels are shaded from dark to light, with the darker pixels forming the shape of a spiral galaxy. The colour scale to the right of the graphs shows that this image is a negative, so that light pixels show areas of least brightness, while dark pixels show the areas of greatest brightness.