OK, I will come back to James idea, <SNIP>... But I'm not fully satisfied by this solution because, what about Earth?
I will cross fingers but I suppose it wouldn't be enough!!!
Best regards.
Nice!
This time you've got it right!
It seems that James was a bit slow, shy, or both to transform his question into a full answer so the winner is.. YOU, with an honorable mention to James for adventuring so far to find a good hint.
These are the symbols for three of the four basic elements in Alchemy: Air, Water, Fire and Earth.
I'll explain: our company develops Naval (water), Flight (air) and Space (fire) simulators. We don't have anything on the ground - at least not at this moment - hence the "missing" Earth element.
Thanks for participating!
/Admin