Bird Migration
Sketches in Illustrator
Movement: The red group moves leftward in steps of 3 squares each turn.
Arrowhead Leader: The bird at the arrowhead (the filled red square) changes position by jumping one place and alternating between the two sides of the arrow.
Movement: The blue group moves leftward in steps of 6 squares each turn.
Arrowhead Leader: The bird at the arrowhead (the filled blue square) changes position by jumping one place on one side of the arrow. When it reaches the end of one side, it starts jumping from the beginning of the arrowhead on the other side in the same manner.