#for (1..2) {
#   foreach my $x (0) { print $x++; }  # Error!
#}

for (1..2) {
   foreach my $x (0..1) { print $x++; }  # 01, 01
}

for (1..2) {
   foreach my $x (0..1,5..6) { print $x++; }  # 0156, 1267
}