We present a rewrite based method to design FPLA combinational
circuits. It is based on the maximal unit strategy method with
built-in algebras. Basic operations on natural integers and boolean algebra 
are done by the use of efficient usual methods. The formalism of 
constraint is used\,;\,efficient, correct heuristics and goal-oriented 
deletion criteria and 
strategies are used without losing correctness and completeness.  
A beta version named CDR (for Circuit Design by Rewriting),
of our method is under experiment. A brief description of CDR and 
some results are presented at the end of the paper.