All values should be undefined: $vara = [+ $vara +]
$varb = [+ $varb +]
$c = [+ $c +]
$d = [+ $d +]
$e = [+ $e +]
First of all assign a value: [- $vara = '(this is the value in $vara)' -]
Now we have some 'Umlaute': [- $varb = "$vara äöü" -] Now lets look what we are getting from this:
[+ $vara +] [+ $varb +]
And now a and b together: [+ "$vara$varb" +]

Here we have some HTML tags within the perl code, Embperl will delete them!
[+ $c =
6 + 17 * 3 +] Embperl will also translate HMTL escapes to the right characters i.e. $vara &lt; 6 will get the perl expression $vara < 6:
[- $e = 2 -] [+ $d = $e < 6 +] Now they should have a value $vara = [+ $vara +]
$varb = [+ $varb +]
$c = [+ $c +]
$d = [+ $d +]
$e = [+ $e +]

Ok.