Dim U As Single = 160, V As Single = 160
Dim H As Single = 0.5
For K As Single = -160 To 160 Step 20
    Dim X As Single = -160
    Dim Y As Single = -K * X * X / 15000 + K
    Dim X1 As Single = Int(U + X + H), Y1 As Single = Int(V  Y + H)
    For X = -150 To 160 Step 10
	   Y = -K * X * X / 15000 + K
	   Dim X2 As Single = Int(U + X + H), Y2 As Single = Int(V  Y + H)
	   e.Graphics.DrawLine(Pens.Black, X1, Y1, X2, Y2)
	   X1 = X2 : Y1 = Y2
    Next
Next
e.Graphics.DrawRectangle(Pens.Black, 0, 0, 320, 320)
