Const dpi As Integer = 360 '(300 is OK for laser one, 360 likely for inkjet)
Const size As String = "A4"

Dim As String filename = "Pinstripe-printer-FreeBASIC.bmp"

Dim As Integer w, h ' paper size in pixels
If size = "letter" Then
    w = 8.5 * dpi
    h = 11.0 * dpi
Elseif size = "A4" Then
    w = 8.2677165 * dpi
    h = 11.6929134 * dpi
End If

Dim As Integer gap = Int(w Mod (dpi * 8) / 2)
Dim As Integer rows = Log(8 * dpi) / Log(2)
Dim As Integer alto = dpi * 0.8

Screenres w, h, 32

' Set background to white
Line (0, 0) - (w - 1, h - 1), Rgb(255, 255, 255), BF

' Draw the black lines
Dim As Integer y = gap
For row As Integer = 0 To rows - 1
    Dim As Integer x = gap
    Dim As Integer ancho = 8 * dpi / (2 ^ row)
    Do While x < (dpi * 8)
        Line (x, y) - (x + ancho, y + alto), Rgb(0, 0, 0), BF
        x += ancho * 2
    Loop
    y += alto
Next row

Bsave(filename, 0)