I have received an absolutely wonderful piece of engineering in Jane's card this week.
It is impossible to photograph in a way that shows it properly so I will have to describe it to you.
There are two sheets of acetate, joined together but with a space between them... a bit like a double glazed window. On one "window" there is green vegetation.
and on the reverse window there are ferns. But the very best bit is between the layers, where there are little beetles that can move about and hide in the vegetation as you move the postcard.
And as if that wasn't enough, Jane sent me a second amazing card with some more clever engineering. The tiger sits in his circus cage... but when you pull the tab...
He disappears and a lion appears in his place. Totally brilliant!