It occurred to me that this is probably easiest to set up in local multiplayer with two controllers. However, before I could get around to this I got it legitimately against the beginner AI. This is pretty easy to do too once the AI stumbles upon an open block and multi-clears a large field for you to pick over. In either case you'll want to adjust the move timer a few notches above the default to allow yourself time to set ten consecutive flags. Setting a flag does not reset your move timer. You need to set them all quickly one after the other.