How to create checkboxes in FPDF? [duplicate]

This question already has an answer here:

• Setting checkboxes and radiobuttons with FPDM in PDF form 3 answers

I'm using FPDF to create a PDF file with checkboxes in it. It doesn't have to be 'real' dynamic checkboxes, just has to look like checkboxes (squares) so it can be used after printing the pdf file.

Since I cannot use html in FPDF I don't know how to create these.

Code example:

$pdf->Cell(15,15,'Title',0,0);
$pdf->Cell(15,15,'[CHECKBOX-1 HERE]',0,0);
$pdf->Cell(15,15,'[CHECKBOX-2 HERE]',0,0);

What do I have to put in the place of [CHECKBOX-X HERE] ? Do I have to work with symbols instead or how is this done? Thanks for your help.