With a sewing machine, create simple beanbags in a variety of shapes with cotton. To do this, cut out small pieces of cotton in basic shape patterns. Use items around the house as templates. For instance, you could trace a remote control for a rectangle or a spaghetti jar for a circle. After you've cut out pieces of cloth, sew them together, right sides together, a leave a small opening. Turn the shape right side out, and fill the shape with beans. Sew the small opening shut. On the floor of your classroom, make large shapes with masking tape. Then, have students stand several feet back, and try to throw each beanbag shape into its masking tape floor counterpoint. Have students say the name of the shape as they throw it.
Before class, hide many construction paper shape cutouts in your classroom. Include every shape, and use a variety of colors, too. Give each student a paper lunch-sized bag with a shape drawn or glued to the outside. If you have many students, change up the color, too. For instance, two students might have a circle, but one has red, and one has blue. Then, give students time to go on a treasure hunt to search for their matches. Have them put their matches in their paper bags. If you're working with fewer students, don't make them worry about the colors, and allow them to get more of their shape in any color.
Help your preschool students learn about triangles and diamonds with a diamond matching game. This game helps students see how two triangles can turn into a diamond and how shapes and colors match each other. To do this, cut out dozens of different colors and sizes of diamonds and triangles. Make at least two of each shape and color so that students can match the shapes. Laminate your shapes to make them last longer, if you wish. Then, have students manipulate the pieces that are simply triangles into diamonds, and have them try to match their pieces. If you would like, you could put fabric fastener on the backs of the diamonds and triangles and put some on a bulletin board or a large white paper. Allow students to manipulate their shapes with the fabric fastener to put matching colors and shapes next to each other.