Rotations, vibrations, winding staircase motions, as well as coriolis accelerations http://en.wikipedia.org/wiki/Coriolis_effect and many others noninertial cyclical motions all attested to the existence of temporal frequency and spatial frequency. Temporal frequency can be used to describe the local oscillation of time. Spatial frequency can be used to describe the local oscillation of 3D space. However, the oscillation of local spacetime would be described by the constant change of state between temporal and spatial. This constant without the interacting neighboring matter is approximately one nanosecond per one unit of feet, whose reciprocal is equivalent to light speed in pure spacetime.