Related Clues:

• Tidal patterns, e.g
• Economist's study
• Rinse and dry
• Sequence of songs
• Recurring sets of changes; groups of songs
• Rides for ages
• Periods; bikes
• Rides in circles
• Wash, rinse and spin
• The four seasons and others
• Rinse and spin
• Pedals for periods
• Repetitive patterns
• Takes a spin class
• Dishwasher stages