Resource Management and 2D Graphics Rendering - Marmalade SDK Mobile Game Development Essentials - page 56

The following diagram shows the types of polygons supported by IwGx. Note that it
is possible to draw more than one polygon at a time by providing longer streams of
data. This is something we should try to do as much as possible, since it prevents the
GPU from idling while it is waiting to be supplied with new polygon information.
The numbers labeling the vertices in the diagram correspond to the elements of the
index stream. When rendering, the indices array is traversed in the order shown for
each polygon type, and the values it contains indicate which element of the various
input streams should be used to render each vertex.