The riddle presents a mystery with clues that lead to a familiar object – tires. Tires are indeed circular, but unlike edible items, they serve the vital role of keeping vehicles and machinery in motion. They are engineered for durability, traction, and support, allowing cars, trucks, bicycles, and countless other vehicles to travel efficiently. Furthermore, the riddle's mention of "usually come in fours" alludes to the fact that most vehicles, especially cars, have four tires. The synergy of these traits encapsulates the essence of tires. This riddle underscores the importance of these unassuming, yet essential, components of modern transportation, playfully challenging our perceptions by highlighting their circular nature while emphasizing their utilitarian purpose.