Related Clues:

• Alternately
• The way ferries go
• How pendulums swing
• Way to sway
• The way ferries travel
• Back and forth
• How a pendulum swings
• One way to sway
• How pendulums move
• Way of swaying
• Bidirectional
• There and back
• Backwards and forwards
• Back and forth, this way and that
• This way and that, back and forth