Weird signs on the highways in Northern Alberta?

Question

I've seen these signs for years and I always wonder what they are for. It's a black sign about a foot square, posted below "real" signs, they have a club, spade or diamond on them and an arrow telling you to turn or not. I've seen them a lot around Edmonton, but they might be other places too.

Answer 1

they are strange signs,ive seen them aswell