The attached datafile does not splot as I would expect. There are no points
that correspond to a line joining the y=7/23 data to the y=7/24 data, yet I
see lines. I expect all lines to be joining points at y=7/23 or y=7/24,
never between one point on one date and another point on the other date. I
guess I have arranged my data incorrectly, but I can't really see what's
wrong. Anyone have any ideas?