The Gauss-Rees waveform has many applications including use in a method for identifying an object, the method including the steps of: directing a primary acoustic waveform at the object to produce a nonlinear acoustic effect; receiving a secondary wavelet produced by the nonlinear effect; and processing the received secondary wavelet in identifying the object. The present invention also provides numeric objects having a growth property. Therefore, an application can access the nearest CRL database to determine whether a digital certificate has been revoked via a set of unified APIs without bothering the detailed of CRL distribution mechanisms. The upper teeth of each rack gear drive a first gear of a pair of coaster gears.