Eights on Pylons or Pylon Eights, is a ground reference maneuver where an aircraft is
flown in a figure eight pattern around two selected points on the ground (the pylons).

However, Eights on
Pylons differs from similar maneuvers such as Eights Along a Road, Eights Across a Road, or
Eights Around Pylons in that the objective of Eights on Pylons is not to maintain a specific
altitude and ground track, but rather to fly the airplane so that the pylon remains fixed in place
when viewed from the cockpit along a line parallel to the lateral axis of the aircraft. This is only
possible when the aircraft is flown at the pivotal altitude

Pivotal altitude

Pivotal altitude is the altitude for a given ground speed at which the line of sight from the cockpitdirectly parallel to the lateral axis of the aircraft will remain stationary on an object on the ground....

 corresponding to the current groundspeed.
If the aircraft is flying in wind, the groundspeed will vary throughout the maneuver and thus
the pivotal altitude will change also. However, the pivotal altitude varies only with the
ground speed and not with the radius of turn or the angle of bank. So whether the maneuver
is flown very close to the pylon with the aircraft banked 60 degrees, or farther from the pylon
at 30 degrees bank, the necessary altitude is the same.

In the United States, the Federal Aviation Administration

Federal Aviation Administration

The Federal Aviation Administration is the national aviation authority of the United States. An agency of the United States Department of Transportation, it has authority to regulate and oversee all aspects of civil aviation in the U.S...

 requires pilots to demonstrate
Eights on Pylons to obtain a Commercial Pilot License.