Function construct::mz

pub fn mz<T: 'static, U: Float>(
    z: U, 
    a: Arc<Fn(T) -> [U; 3] + Sync + Send>
) -> Arc<Fn(T) -> [U; 3] + Sync + Send> where
    f64: Cast<U>, 

Mirror shape 1d -> 3d around xy-plane at z coordinate.