basic normal calculation

normals.pl6

sub vector-to-unit( @vec ) { @vec >>/>> sqrt( [+] @vec >>**>> 2 ) }
sub cross-product( @v1, @v2 ) { 
    ( @v1[1,2,0] >>*<< @v2[2,0,1] ) 
    >>-<< 
    ( @v1[2,0,1] >>*<< @v2[1,2,0] )
}
sub surface-to-normal( @a, @b, @c ) {
    my @b2 = @b >>-<< @a;
    my @c2 = @c >>-<< @a;
    my @normal = cross-product( @b2, @c2 );
    return vector-to-unit( @normal ); # what's a normal if it's not actually normal?
}