...This homely scene of maternal affection is also a powerful piece of Christian symbolism. While the cat on the left is playing with the Virgin's hem, a snake can be seen slithering out from under her skirt. The Virgin is treading on the snake, symbolizing her role as the new Eve, who will triumph over original sin. Joseph looks in from outside the window... (https://en.wikipedia.org/wiki/Virgin_and_Child_with_a_Cat) Rembrandt produced 290 etchings during his life; in his hand the etching became a true work of art in its own right. To this day he is widely considered to be the most accomplished etcher of all time. His preoccupation with light and shade is seen throughout his work. In his monochrome prints he achieved results which were as expressive and varied as in his oil paintings. ...Rembrandt achieved unsurpassed effects of light and darkness purely through the combination of black lines and the white space around them. (http://arthistorynewsreport.blogspot.nl/2017/11/)