Source : Free On-Line Dictionary of Computing

reinvent the wheel
     
         To design or implement a tool equivalent to an
        existing one or part of one, with the implication that doing
        so is silly or a waste of time.  This is often a valid
        criticism.  On the other hand, automobiles don't use wooden
        rollers, and some kinds of wheel have to be reinvented many
        times before you get them right.  On the third hand, people
        reinventing the wheel do tend to come up with the moral
        equivalent of a trapezoid with an offset axle.
     
        [{Jargon File}]
     
        (1997-04-12)