Unusual sing uncovered from heavy rain

[okitrip]

Today i find this ,,signs,, on heavy rain
This normal wall when weather its dry but when rain i see this like angel.
So i ask you all what that mean ?

 

Amazon Forum Fav 👍

Agony and Death on a Gold Rush Steamer: The Disastrous Sinking of the Side-Wheeler Yankee Blade - Grab it through Amazon!

[okitrip]

Better picture