Nanotube manipulation (main screen):
The main screen displays the location of carbon atoms in 3D.
Reset angle: Double tap anywhere on screen. (Sets view to look directly down the nanotube axis.)
Auto-rotate: Tap rotate icon in lower-left corner.
Change nanotube structure: Tap construction icon in upper-right corner. (This brings up the flip screen.)
Change drawing modes: Tap an image in upper left corner. (Changes how atoms and bonds are displayed.)