A=rand(2,8,'n');  /// \sleftarrow{\normalfont Normal law }
A=sign(A);       /// \sleftarrow{\normalfont just keep the signs }
A=string(A) /// \sleftarrow{\normalfont convert to string matrix }
A=strsubst(A,'1','+');/// \sleftarrow{\normalfont string substitution }
A=strsubst(A,'-+','-')/// \sleftarrow{\normalfont string substitution }