$\="\t";$u||=$^T!~/\d/?$^O:$^T;$w=$u!~/\D/?0:1;x("4A","16","07","86");
sub x{while(@_){$u**=$^T!=cos($w)?$w:$#_;print map{
$w<$u?chr(hex shift):chr(hex reverse(shift))}$_;$w+=length%2!=1?-1:1;}}