Extruding Polygon Edges
Maya 2012 Tutorial
How to Add Faces by Extruding Edges in Maya
Starting with a simple polygon object, you can extrude the exterior faces to add more geometry. Another method of adding complexity to a polygon object is the append faces method. For more information, see topic Adding Faces to Polygon.
Using the Polygons menu set choose Mesh > Create Polygon Tool and draw a four sided polygon. Click four times in a counter-clockwise direction, then press the Enter key.
Switch to the Component Mode and activate the Edge Selection. Shift click to select all the polygons exterior edges. A second edge selection method is to choose Select > Select Border Edge Tool and double-click one of the edges.
With the edges selected and in the Polygons menu set, choose Edit Mesh > Extrude. Drag the extrude arrow in an outward direction. Press the q key to return to the select tool and exit or press the g key to extrude again.