It is an example of artists take elements from the environment to transform and represent their mood and messages.
        
                    
             
        
        
        
They are Isotypes, a form of pictoral (picture) language
 
        
                    
             
        
        
        
Reclamation of land from the sea. 
Hope this helps! <3
        
             
        
        
        
The layer mask hides parts of a layer without damaging any part of an image.
It is possible to ad<span>d a mask to a layer and uses the mask to hide portions of the layer and reveal the layers below. This is a valuable compositing technique for combining multiple photos into a single image or for removing a person or object from a photo.</span>