00423nam a2200157Ia 4500008004100000020001300041082001500054100002100069245003800090250000700128260003700135300002900172500000700201600003300208650002400241240925s9999    xx            000 0 und d  a76101986  a793.74 MAR  aMartin , Gardner 0aPenrose tiles to trapdoor ciphers  aNA  aNew York:bW. H. Freemanc,1989.  aviii,326p.bNAfOriginal  aNA  aHumanities & Natural Science  aArts and Recreation