Row of Symbolic Posts?

A view of a part of London Bridge Ocean Beach on the Mornington Peninsula.
I understand why the fence on the left exists - to help walking down steep steps to the beach.
But why the isolated, unconnected posts along the sands?
Like a symbolic warning of unstable sands?

Enigmatic posts
Stirring some careful answers
Like lost boundaries

Linking to:
Thursday's Things in a Row 

Mysterious Yard Art at Flinders

Pic by Gemma Wiseman ~ In the front garden of a Flinders home, Westernport Bay, Mornington Peninsula are these unusual features.
They seem to mark the corners of a triangular garden bed.
But why?
~
Yard Art on Thursdays meme
~

Triangular shape
Tall wooden cross-like features
Spiritual tone
~

MY NEW MEME
Weekend Mailbox #8 is HERE
Ned Kelly and a singing postman are there! Check them out!
AND
MY NEW MEME
Weekend Nature #3 is HERE!