Although McLean's work is abstract, he has commented that 'painting abstractly doesn't mean independence of the natural world. The most obvious aspect of the natural world that affects my work is light'. One of McLean's concerns is the way colour can be used to suggest light and space. The title of this work alludes to the capacity of certain colours to be read both as solid shapes and as apertures in the surface of the painting. Here, for example, the yellow shape can be seen as an opening, and the blue shapes as surrounding walls of colour. However, it is also possible to reverse this impression and read other colours as implying space.