[SOLVED] $_GET variable, as a variable itself (variable squared?)

[xProteuSx]

OK, I am trying to call up a form variable, which is a variable in itself, as below:

 

$whatever = $_GET[$blah];

 

I cannot get this to work.  I have also tried:

 

$whatever = $_GET['$blah'];

$whatever = $_GET['' . $blah . ''];

$whatever = $_GET['"$blah"'];

 

I really don't know ... and can't figure it out.