sub LOW_PRE_PI {3.141}
sub HI_POST_PI () {3.142}

my @n_proto = (1, LOW_PRE_PI + 5, 11, 15);
my @y_proto = (1, HI_POST_PI + 5, 11, 15);

print "@n_proto\n@y_proto";
__END__
Output:
1 3.141
1 8.142 11 15