The Boundary Jack.

A jack driven onto the side boundary remains live.
The Boundary Jack Still In Play
Players may play toward it from either side, even though the bowl passes outside the boundary.
Resting Inside Rink Is Live.
A bowl coming to rest within the rink remains live even if it missed the boundary jack [1].
Resting Outside Rink Is Dead.
A bowl coming to rest outside the rink is dead even if it touched the boundary jack [2].