Impossible? No, just unlikely.
This Fire Ambigram is a nice short symmetric ambigram that at first glance doesn't quite seem possible.
A quick glance will show you that you can read this as 'Fire' when the design is upright and also as 'Fire' when the design is inverted (or is it the other way around?).
To rotate the design, just move your mouse over the image.
Would you like to see other options? See an entire gallery of choices by clicking the Create New Design button.
Select This Design Create New Design