pub fn mx<T: 'static, U: Float>( x: U, a: Arc<dyn Fn(T) -> [U; 3] + Sync + Send>, ) -> Arc<dyn Fn(T) -> [U; 3] + Sync + Send>where f64: Cast<U>,
Mirror shape 1d -> 3d around yz-plane at x coordinate.
1d -> 3d