You can fence two adjacent sides, say north and west, and have another fence from the center to the southeast corner. That's 2+(1/sqrt(2))~2.707. The number I

You can fence two adjacent sides, say north and west, and have another fence from the center to the southeast corner. That's 2+(1/sqrt(2))~2.707. The number I got was from keeping the center to SE corner fence, and finding three straight fences to join the remaining three corners. I assumed these three meet at one point and that the point is on the NW-SE diagonal.