How things change over time can be frightening but also fascinating! Statues and sculptures of limestone or other more sensitive materials is heavily affected by what we call Acid rain. As the rain falls on the material, it slowly starts to eat of parts, little by little, until you no longer can recognise the initial motive. The method of making something finished, straight or closed, to later remove chosen or random parts is a method used in many fields, art, architecture etc. Siri Derkert osed this way of working on her artwork in the subway station Östermalmstorg in Stockholm. So by first covering a dark part of the wall In white concrete, and later apply force to revel the underlying color and then create lines.
Lime stone statues effected by acid rain.
First image: Unknown
Second image: Rheims Cathedral, France
Siri Derkert working on her art, Stockholm