My late Mudcatter friend Deckman (Bob Nelson) was a carpenter of some renown in his area (with a museum-quality collection of wood-working tools in his garden shed). He also lived near a busy street and was tired of scraping up pet cats, so built a chicken-wire-clad structure of 2x4s that had a wire tunnel boxed in from a bedroom window and included a small tree near the house. Imagine a chicken wire bubble on the side of the house that was a cube up to maybe 10' on each side and tall. They could get out and still stay safe.