Процедура преобразования от четырех векторов

program boo;  
var i:integer;
a,b,c,d:array[1..100] of real;
procedure Peretvorennya(x:array[1..100] of real; y:array[1..100] of real); 
begin for i:=1 to 8 do 
x[i]:=a[i];
for i:=9 to 20 do 
x[i]:=a[i];
for i:=10 to 20 do
x[i]:=c[i];
for i:=1 to 5 do
y[i]:=d[i];
for i:=6 to 11 do 
y[i]:=a[i-5];
for i:=12 to 16 do
y[i]:=d[i];
y[17]:=a[1]; end;
begin randomize;
     for i:=1 to 20 do
a[i]:=random(50); b[i]:=random(50);c[i]:=random(50);d[i]:=random(50);
             writeln(a,b,c,d);
             Peretvorennya(x,y);
             writeln(x,y);
end.

type
  myArray = array [1..20] of Real;
 
procedure transformation(a, b : myArray; var x, y : myArray);
begin
  /// массив x
  for var i := 1 to 8 do x[i] := a[i];
  /// массив y
  for var i := 6 to 11 do y[i] := b[i - 5];
  for var i := 17 to 20 do y[i] := a[1];
end;
 
var
  a, b, x, y : myArray;
  
begin
  for var i := 1 to 20 do
    (a[i], b[i], x[i], y[i]) := (Random(50), Random(50), Random(50), Random(50));
  WriteLn('a : ', a, NewLine, 'b : ', b, NewLine, 'x : ', x, NewLine, 'y : ', y);
  transformation(a, b, x, y);
  WriteLn('Transformation:', NewLine, 'x : ', x, NewLine, 'y : ', y);
end.