The Cross Layout draws the focused window in the center of the screen and part of the other windows on the sides. The Shrink and Expand messages increment the size of the main window.

The focus keybindings change the center window, while other windows cycle through the side positions. With the Cross layout only four windows are shown around the focused window, two ups and two downs, no matter how many are in the current stack. I.e. focus down cycles the window below focused into the center; focus up cycles the window above.