A gray modeling clay is found in a bright white room. It leaves traces, but strives to keep the room in its original state, as long as the boundary of its space will not change one day.
1929
2017
2020
1940
2003
2008
2019
2018
1981
2015
1955
2010
1923
1971
2009
2011
2014
1995
1998