Okay, here at Sust Larki's suggestion. The rule is that you post one line each of a haiku (first line 5 syllables, second 7, third 5), and at the end of three lines you have a little poem - so continuity is very important.
[By the way, I suggest that the second contributor posts both lines, and the third contributor all three, so we can see the thing more clearly as it builds.]