Similar to Simon Says....
All standing in line across hall.
Leader shouts â€œOâ€™Grady say do thisâ€, and makes action; others follow suit.
If leader shouts â€œDo thisâ€ (i.e. no â€œOâ€™Grady saysâ€) then anyone who does it falls back one pace.
Continue until bored or some other criteria, e.g. someone has fallen back three paces.