Methods herein relate to aligning objects and can include aligning a transmitter and a receiver to establish a reference line, advancing one or more objects in a direction of advance toward the reference line, interrupting the reference line with the one or more objects and withdrawing the one or more objects opposite the direction of advance until the reference line is uninterrupted. Alternative or complementary aspects relating to alignment can include detecting an interruption of the reference line based on an object entering the path between the transmitter and the receiver, transmitting an interruption signal based on the detected interruption of the reference line detecting a reestablishment of the reference, and transmitting a continuity signal based on the detected reestablishment of the reference line. Systems for effecting such techniques are also disclosed.