My first grader came home with it from art class the other day, and the concept is quite smart and at the same time, easy enough for six year old fingers to handle. Younger kids shouldn't have too much trouble either.
I love simple and easy, especially simple and easy made with things we already have around the house.
The kids started with large pieces of black construction paper. They each used white chalk to draw a snowman or winter scene on a regular sized piece of blue construction paper; I'm guessing blue because the sky is blue. The blue sheet was glued onto the black sheet, slightly off center. Then a 3/4" inch strip was cut from one long side and one short side of the black construction paper and crisscrossed on top of the blue paper to form a window pane. Staples and or glue were used to put it all together.
Looked at from afar, it really looks like you are looking out of a window and seeing a snowman. Very cool.