Type
  TPoint =
    Record
      X, Y: Integer;
    End;

Function min(a, b: Integer): Integer;
  Begin
    min := a;
    if b < a Then min := b
  End;

Function max(a, b: Integer): Integer;
  Begin
    max := a;
    if b > a Then max := b
  End;

Function isInside(Const a: Array Of TPoint;
         b: TPoint; n: Integer): Boolean;
  Var
    i, j, Count: Word;
    T: Double;
  Begin
    Count := 0;
    For i := 0 To Pred(n) Do
      Begin
        j := (i+1) mod n;
        If a[i].Y = a[j].Y Then Continue;

        If (a[i].Y > b.Y) and (a[j].Y > b.Y) Then Continue;
        If (a[i].Y < b.Y) and (a[j].Y < b.Y) Then Continue;
        If (max(a[i].Y, a[j].Y) = b.Y)
          Then Inc(Count)
          Else
            Begin
              If min(a[i].Y, a[j].Y) = b.y Then Continue
              Else
                Begin
                  T := (b.Y - a[i].Y) / (a[j].Y - a[i].Y);
                  If a[i].X + T * (a[j].X - a[i].X) >= b.X Then Inc(Count)
                End
            End;
      End;
    IsInside := ((Count and $0001) <> 0)
  End;


Function PointInSidebar(Const SideBar: Array Of TPoint;
         p: TPoint; Count: Integer): Boolean;
  Var
    x1,y1,x2,y2: Double;
    x0, y0, sum, divisor: Double;
    i: integer;
  Begin
    sum := 0;
    y0 := p.y;
    x0 := p.x;
    For i := 0 to Pred(count-1) do
      Begin
        x1:=sidebar[i].x;
        y1:=sidebar[i].y;
        x2:=sidebar[i+1].x;
        y2:=sidebar[i+1].y;

        divisor:=y1*x2-x1*y2-y0*x2+y0*x1+x0*y2-x0*y1;
        divisor := divisor + 1.0E-10;

        Sum := sum + (
        -arctan( (-x2*x1+x1*x0+y0*y1-x2*x0+x2*x2-y2*y0+y2*y2-y1*y2 )/divisor)+
        arctan( (-x1*x1+x2*x1+x1*x0+y0*y1+y1*y2-x2*x0-y1*y1-y2*y0 )/divisor)
        );
      End;

    x1:=sidebar[count-1].x;
    y1:=sidebar[count-1].y;
    x2:=sidebar[0].x;
    y2:=sidebar[0].y;

    divisor:=y1*x2-x1*y2-y0*x2+y0*x1+x0*y2-x0*y1;
    divisor := divisor + 1.0E-10;
    Sum := sum + (
    -arctan((-x2*x1+x1*x0+y0*y1-x2*x0+x2*x2-y2*y0+y2*y2-y1*y2)/divisor)+
    arctan((-x1*x1+x2*x1+x1*x0+y0*y1+y1*y2-x2*x0-y1*y1-y2*y0)/divisor)
    );

    pointinsidebar := not (abs(Sum) < 0.0001)
  End;

Const
  arr: Array[0 .. 3] Of TPoint =
    (*
    ( {First}
      (X:3;Y:3),
      (X:7;Y:10),
      (X:12;Y:6),
      (X:9;Y:7)
    );
    *)
    (*
    (
      (X:12;Y:8),
      (X:17;Y:14),
      (X:17;Y:11),
      (X:21;Y:7)
    );
    *)
    (
      (X:1;Y:2),
      (X:1;Y:4),
      (X:3;Y:4),
      (X:3;Y:2)
    );

Const
  (* {First}
  Check1: TPoint = (X:4; Y:8);
  Check2: TPoint = (X:7; Y:8);
  Check3: TPoint = (X:7; Y:5);
  Check4: TPoint = (X:9; Y:5);
  *)

  (* {Second}
  Check1: TPoint = (X:13; Y:12);
  Check2: TPoint = (X:16; Y:10);
  Check3: TPoint = (X:18; Y:11);
  Check4: TPoint = (X:19; Y:8);
  *)
  Check1: TPoint = (X:1; Y:3);

Var
  b: Boolean;
Begin
  b := PointInSidebar(arr, Check1, 4);
  {
  b := PointInSidebar(arr, Check2, 4);
  b := PointInSidebar(arr, Check3, 4);
  b := PointInSidebar(arr, Check4, 4);
  }
End.