I write this chapter using a MacBook Air. To accomplish this task, arranged on my computer desktop are the following: a Microsoft Word file containing a draft of the chapter; another Word file of notes; an internet browser with multiple tabs; a file management box, with lists of folders in which I can find further chapters, notes, and pdfs; and Spotify, a music player. I have listed these programs in their order of recession – that is, the Word file of the chapter is at the perceptual forefront (apart from the ever-present arrow of the cursor which I move around the desktop) and all the other programs are partly concealed, slid beneath both the chapter file and one another, such that sections of program windows peek out in an overlapping constellation on my 13.3-inch screen. I tell myself that this arrangement is convenient for switching between all these sources of information as and when the need arises: I can easily manipulate all the open programs to change their order and placement, bringing the file management window to the fore and moving the browser to the back, for example. The interleaved approach also allows me to keep a sneaky eye on my emails while engrossed in other tasks.

But this arrangement is by no means fixed. When the need arises, I can reposition all these windows both in space and in perceptual depth – for instance, I can bury the internet browser beneath everything else so that, while it is still present and open, I won't actually see if any new emails appear within its window. During such reshuffling, program windows and the onscreen cursor move fluidly, sliding around the screen with flowing clarity and laser-like precision. This rearranging can also reveal what lies behind all these open windows – namely, an image of Lone Pine Peak, a rock formation in California, captured in the early morning light. Bundled with the OS, this natural scene suggests even more depth – it is a distant landscape photo, after all – but the image itself signifies the very back and limit of the screen's navigable, overlapping space.