CAPTURE BY A SWARM
Flocking behaviour in Stage (3.2.2) can be realised by using 'pioneer_flocking' Stage controller. The default settings simulates 100 robots which exhibit swarm behaviour by forming flocks.
A interesting feature of a swarm is that it can 'capture' other robots in its path. The captured robots behave as a part of the swarm.
1/3 - Initially there are 100 red robots and 3 yellow robots. On starting simulation the red robots start to move, triggered by sonars bouncing off the wall, while the yellow robots are stationary.
2/3 - The red swarm on reaching the yellow robots 'capture' them.
3/3 - The captured yellow robots behave as a part of the swarm.
Codes for the simulation are available here
(1) Richard Vaughan, "Massively Multiple Robot Simulations in Stage"