|   | 1 |  initial version  | 
According to the Sage tutorial:
You can combine several plots by adding them.
So try:
sage: P = polygon([(0,0), (1,1), (0,1)])
sage: Q = polygon([(1,0), (1,1), (1.5,2)], color='red')
sage: C = circle((0,1), 2)
sage: P + Q + C
 Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.
 
                
                Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.