Three red boxes will appear in the center of the screen:
[+] zooms in [-] zooms out [>] toggles pan/selection mode [pan mode] allows you to move layout by clicking on area and dragging [selection mode] allows you to magnify particular area [*] indicate areas where comments appear with mouse-over; an arrow will point in the direction of the comment if the comment window is outside the viewing frame
» Introduction, by W. J. T. Mitchell,
Eduardo de Almeida, and Rebecca Reynolds (coming soon)