I have completed my square :
And I was very confident to finish the border for the 3rd square this evening and send the RR to the next person and............as I was happily stitching the outline away and whattt???? I miscalculated one of the sides and the lines did not meet at the corner! See this :
Now I have to frog the border (again!) and SMS'ed my partner that I couldn't make it tonight. I feel very bad..................Sorry Nik!
P/S - Can you spot the mistake?