has been installed after an inquisitive sheep leapt onto the roof of a hospital in North Wales.
However, it seems the sheep simply wanted to graze.
The hospital, in Ysbyty Alltwen, near Porthmadog, Gwynedd, was designed to blend in with the surrounding natural environment and was built with a green eco-roof planted with sedum, which can look like grass, the Daily Post reports.
While there is normally a drop of several foot between the cliff face of Craig-y-Castell and the top of the building, a contractor had parked his car halfway between, giving the sheep a handy stepping stone.
The animal leapt onto the roof and was quickly rescued, the newspaper reports.
To prevent it happening again, security fencing
has been deployed at the edge of the cliff face.
The hospital, built last year, has won two awards from The Green Organisation, an environmental group, for its green credentials.
A spokesperson for the organisation told the newspaper: "This story shows they have clearly succeeded in fitting in with the local environment and that the award was well deserved."