Hello, and welcome to our next feature here at Postcard of the Day: it's Evans Plunge, pictured here on a card from my family of origin's old papers. In this one you can see the rocks on the bottom of the pool. I'd forgotten they were there until I swam here with a gf years later.
On the back the child me wrote the key to a code I'd apparently made up.
Secret Blinking At 10:00pm
1 blink -- Hi
2 blink -- I will play with you tomarrow
3 blink -- bring yarn
4 blink -- I will call
5 blink -- bring hot wheels
6 blink -- call robbie An ol(?) Fool