Parts of your robot can extend in any direction from the starting position as long as the robot is never longer than 20 inches nor wider than 11 inches. This length and width are relative to the plane of the field floor at the robot’s starting position (that is, if a maximum footprint robot was to to one side, it doesn’t violate .
For example: a robot that starts out as a 10-inch cube then raises a mechanism up vertically from its center that then raises a horizontal beam toward the front of the robot that is 10 inches long would not violate the rule (the overall length would be ~15 inches, less than the 20 inch limit). On the other hand, a robot with a 10-inch square, 5-inch high base that had a telescoping arm with its base at the rear of the robot that starts the match 15 inches long could only extend that arm 5 inches with the arm pointed forward, an unlimited number of inches when pointed straight up, and 0 inches when pointed to the rear without violating .