I actually developed Challenge #73 for the Fast Friday group. The challenge began with a setting: traveling to another planet where the planet's surface is all covered by water and only stone megalithic structures rise above the water. The challenge itself was to incorporate two loops as a design element in a piece. The artist could create a piece using imagery based on the setting mentioned, or take off with his/her own idea.
What I did with loops was to use them for hanging each of three panels. The bottom panel (with really long loops) represents the alien planet. The other two panels function as valances, and one represents day and the other night. Each can easily be flipped in to place.
Title of the piece: The Day and Night Flip!