inverted moons

Love the story about the inverted moons on christmas cards: Your moons are rubbish, astronomer tells Christmas card artists

I should just add that one doesn't need to know about waning moons and what time they rise - it is completely sufficient to know that both Sun and Moon move from left to right in the sky (seen from the Northern hemisphere outside the tropics) and that the bright side of the moon points towards where the Sun is. So in the wrong xmas card, the bright side points to the left, so the Sun is trailing the Moon and will rise in a couple of hours, so it must be early morning. For an evening scene, you want a Sun that has recently set, so bright side of the Moon must point to the right. Simples.

Are these artists the same people who insist on putting inverted helices on the covers of books and magazines, I wonder ...