The Boy has a bedtime routine, like most toddlers - a bit of In the Night Garden (a weird and quite trippy programme), bedtime, then his Dad takes him up to bed cos I tend to do more of the mornings.
Anyway, when he ascends the stairs, the routine goes:
Me: "Goodnight triangle!" (it always starts with triangle).
Him: "Goodnight square!" (normally)
And then we work our way through the shapes as he goes up the stairs. The Boy is very big on shapes. We normally have rectangle, circle, nonagon, hexagon, pentagon... although as I write this I realise we have both forgotten about octagons.
This started because we were trying to get him to say "Goodnight Mummy" but he refused and instead started saying goodnight to shapes instead.
It is a bit geeky. But I love sharing this routine with him.