spock:~ [16:02:30]$ perl -wMstrict -le 'my $x=1; print ${x}'
Ambiguous use of ${x} resolved to $x at -e line 1.
1
spock:~ [16:02:36]$ perl -wMstrict -le 'my $x=1; print ${"x"}'
Can't use string ("x") as a SCALAR ref while "strict refs" in use at -e line 1.