This costume was designed as part of a school project. I had to design a marine invertebrate-themed  costume for a ten- to thirteen-year-old. The costume had to be made of cardboard and use the flat pack construction method. No materials could be used other than cardboard. The costume had to be easily assembled and could not use any fasteners.

Item        Supplies               Quantity                  Size
S1           CARDBOARD              2                       3.5'' by 3.5''

Item    Tools and Equipment                            Use
T1           CUTTING MAT                                     Provides a safe cutting surface
T2           UTILITY KNIFE                                      Cuts cardboard
T3           RULER                                                Measures distances and is used to draw straight lines
T4           PENCIL                                                 Draws
T5           CIRCLE TEMPLATE OR COMPASS   Can be used to draw circles

Step 1: Part P1: the Bottom Shell

1. Use the pencil (T3) to draw a circle, using the circle template or compass (T5), on a sheet of cardboard (S1) with an 18'' radius.

2. Draw a circle with an 8'' radius with the same center as the 18'' circle.

3. Cut out, using the utility knife (T2) on the cutting mat (T1) the larger circle.

4. Cut out the inner circle.

Step 2: Part P1: the Bottom Shell, Continued

5. One inch from the edge of the larger circle, draw (T3) and cut out (T2) a 1.5'' by 1'' rectangle. The 1.5'' edge of this rectangle should be closer to the edge of the circle.

6. Across from that rectangle, cut (T2) a 9'' slit extending from the outer edge of the circle.

7. One-eighth of the circle from that slit on either side, cut (T2) two more identical slits.

8. One-eighth of the circle away from each of those slits, cut (T2) two more identical slits.

9. One-eighth of the circle away from each of those slits, cut (T2) two more identical slits. There should now be seven 9'' slits in the circle.

10. Pull each flap over the next flap clockwise. The circle should now curve inward, forming a dome.

Step 3: Part P2: the Top Shell

1. Use the pencil (T3) to draw a circle, using the circle template or compass (T5), on a sheet of cardboard (S1) with an 18'' radius.

2. Draw (T3) two 1'' parallel lines extending from the circle's edge, 1'' apart.

3. At the end of those lines, draw (T3) and cut out (T2) a 3'' by 1'; rectangle, with the 3'' edge facing the circle.

4. Cut out (T2) the complete shape as one unit.

Step 4: Part P2: the Top Shell, Continued

5. Across from that rectangle, cut (T2) a 12'' slit extending from the outer edge of the circle.

6. One-eighth of the circle from that slit on either side, cut (T2) two more identical slits.

7. One-eighth of the circle away from each of those slits, cut (T2) two more identical slits.

8. One-eighth of the circle away from each of those slits, cut (T2) two more identical slits. There should now be seven 12'' slits in the circle.

9. Pull each flap over the next flap clockwise. The circle should now curve inward, forming a dome.