I have a suggestion for a variation (with Elegran's permission), but I won't cry if you think it's rubbish. We could perhaps have a theme for each round eg Flowers, Music, Books, Holidays etc, and the person who finished a round would choose the theme for the next round. For example if we had a round on the theme of 'Grandchildren' the last poster might write...
'Zits are often a problem for teenage grandchildren, and my choice of theme for the next round is.......'
If we were to play this way I suggest we could start with the theme of 'Food' which seems to be popular with most of us

This variation would make 'the rule' easier to work out for newcomers so maybe for this reason it's a non-starter? But, it would be nice to keep the game going - a good stress-buster on difficult days and easy to dip into as and when one has a few idle moments! Look forward to hearing other suggestions and starting all over again...