Çapraz Yazı Programı

Çapraz yazı
uses wincrt;
var
m:string;
i,l,b:byte;
begin
clrscr;
write('mesaji girin:');
readln(m);
clrscr;
l:=length(m);
b:=2*l-3;
begin
writeln('':i,copy(m,i,1),'':b,copy(m,i,1));
b:=b-2;
end;
writeln('':l,copy(m,l,1));
b:=1;
for i:=l-1 downto 1 do
begin
writeln('':i,copy(m,i,1),'':b,copy(m,i,1));
b:=b+2;
end;
end.