You can divide the display window into either two or four smaller windows. The model in the original window is reduced in display size and shown in the new windows, allowing you to inspect different aspects of the model simultaneously.
 ().   Cross-hairs appear over the window, allowing you to split the window into two or four smaller sections.
 ().   Cross-hairs appear over the window, allowing you to split the window into two or four smaller sections.  Split Horizontally and
  Split Horizontally and  Split Vertically to split a window.
  Split Vertically to split a window.