Mirror Cards were developed to teach spatial relationships and symmetry informally in early grades.* The idea is to place a mirror on some initial card, such as the one in the following figure, to obtain a pattern which is on another card.

1. Using sketches of the initial card above draw a line on each sketch to represent the placement of a mirror to show how each pattern on the following cards can be obtained.

2. Sketch some other figures that can be obtained from the initial card given above and show a line representing the mirror which produces each figure.

3. Design an initial card and show some figures that can be obtained from it. For each figure you obtain, draw a line on your initial card to represent the placement of the mirror.

*M. Walter, "An Example of Informal Geometry: Mirror Cards," Arithmetic Teacher 13 (October 1966): 338-352.