I guess it depends on how you define the "top." Say, the imaginary 2 dimensional surface of a table top or the table top in its 3 dimensional entirety.
Much like these dogs. They're racing their owners on a 2-dimensional plane. but in reality it's a 3-dimensional surface. Whether you define the "top" as the concrete racetrack as a "top" and 2d plane or if you side with the reasoning that the concrete is 3d and provides a relatively smooth surface that can be considered a "top"
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