Things You'll Need
12-by-12-inch cardboard box
Glue gun with glue
A three-dimensional diamond made out of cardboard provides a cheap solution for use as a stage prop or decoration for a party or event. This object consists of two-dimensional symmetrical triangles organized to form a diamond shape. Creating a diamond shape out of cardboard also makes great practice for more intricate cardboard shapes and designs and can help boost your confidence in creating props and decorations.
Draw, on a print-free area of a 12-by-12-inch cardboard box, a triangle consisting of three 6-inch lines with 60-degree angles between them. Use a ruler to get the right lengths and a protractor to get the correct angle between the lines.
Find more open space on the cardboard box and keep drawing the same triangle pattern you used in Step 1 until you have a total of eight triangles.
Cut out each triangle with scissors.
Plug in a hot glue gun and allow it to warm for five minutes.
Put an edge of one triangle next to the edge of another triangle to form a flush, flat plane and create a 90-degree angle at the base of the two triangles when you stand them up. Put the tip of the glue gun on the inside portion where these two cardboard pieces join. Press the trigger on the glue gun and run it along this line. Repeat this process for the remaining triangles until you have four half-pyramid cardboard shapes. Wait eight to 10 minutes for the glue to dry.
Put two half-pyramid pieces together to form a square at the open end of the shape. The two pieces should form a point at the top of the design. Turn this organized section of pieces over on its point and place the glue gun at the edge where the two pieces meet. Press the glue gun trigger and run glue along the edge of the two pieces on both of the unconnected sides.
Hold the cardboard pyramid in place with both hands until the glue has dried to ensure the pyramid maintains its form. Then repeat this procedure with the two other half-pyramid pieces. You should now have two fully formed cardboard pyramids with square open ends.
Place the open square ends of the pyramids together and run the glue gun along the edge where they meet. Hold them together until the glue dries to complete your three-dimensional cardboard diamond.
You can cut out pieces of colored paper and glue them on or use crayons to color the triangular pieces beforehand to brighten the cardboard diamond. Plan your decorations and place them onto the triangular pieces before gluing everything together.
Once the diamond shape has formed, pressure against the cardboard may cause it to collapse.