We've got carpet in our hallway and as it's quite large and we
couldn't afford an expensive runner to protect it, we got some light,
cheap mats which are about 5 feet by 2 feet. they look fine when put
in place but after a day or two seem to migrate to the side of the
hallway opposite the doorways and start crumpling up into a trip
hazard. Is there some sort of double sided tape I could use which
would would keep them in place but which won't damage the carpet
undernearh?