The challenge was actually proposed in August 2013, and, although I had read it at the time, wasn't inclined to make one design by myself. Reading a post by Samuel McKittrick, decided to make a design by myself.
A very summarized plot of the tale is the following (not sure if correct):
Bodb Derg was elected king of Tuatha Dé Danann, with the discordance of Lir (sea god). To pacify Lir, Bod's daughter Aoibh married with him, and the couple had four children. Following the death of Aoibh, that made the children very melancholy, Lir married another Bodb's daughter, Aoife. The jealous Aoife tried to kill the children, but could only manage to transform them in swans. Knowing it, Bodb transformed Aoife in an air demon.Below, you can see six designs: the three on top, by Zachary Harden, was found on original Facebook page, while the bottom three were took from Samuel McKittrick's post.
I really don't believe that this kind of design could have been considered in early 1940s, but I like it nonetheless. On center, there's the coat of arms of Republic of Ireland, a sign of president's headship of state. The four swans, as placed, remember heraldic supporters, on a curious effect.
Your comments are welcome.
Zachary Harden's designs can be found here, with Samuel McKittrick's proposals can be found here.