Summer Infant Secure Surround Gate

We used this sturdy, plastic gate to put the baby swing in. That way, our toddler could not poke the newborn.  You can shape it quite well, so it's rather flexible given your space.
We used a second one out on our balcony so the toddler would not fall under the railing.  We tied it with military ties to the rails.

I have no complaints about this product.  

It folds up easily for storage.  

I know my toddlers would never be happy playing IN it (unless they were older and playing fort), but it has worked to keep them safe as mentioned above. 

The product has good resale value, as parents want these.