Wingsails...

...on a sundial ( not really much use this weekend, but hopefully soon! ) for MonoMonday today.
Sails on boats are sometimes referred to as "wings" especially on more modern high tech craft eg the America's Cup yachts. Sailing terms also include sailing "wing to wing" or "goosewinging" when the wind is directly behind you.
I thought I'd go slightly off piste with today's challenge, as my bird photography is pants, and I'm not sure about my ability to make paper aeroplanes any more... so I offer you instead the boaty sundial in my sister's garden...
Thanks to Nickimags888 for coming up with the ideas this month!