Make a 20-sided die

 

The proper name for the 20-sided solid shape we’d know as a 20-sided die or D20 is an icosahedron. Will you use your finished die to play D&D, or perhaps something else?

 

You will need:

• Paper or thin card
• Pencil
• Ruler
• Compass (optional)
• Scissors
• Sticky tape
• A pen

 

1. An icosahedron is made up of 20 equilateral triangles (where all 3 sides and internal angles are the same). You could choose to print and then cut out triangles.

Alternatively, you’ll need to draw one triangle onto your paper, which you can then use as a template to make 19 more.

 

2. Start by drawing a line on the paper. We chose to make ours 5cm long.

 

3. If you’re using a protractor, now is the time to open it to 5cm and make a small mark at a point 5cm from each end of the ends of the line. Where the marks cross is the third point of your triangle.

 

4. In case you don’t have a protractor, we’ll show you how to make an equilateral triangle using just a pencil and ruler. Mark a point half way along the line you made in 2.

 

5. Draw a feint line straight upwards from this halfway point and extending beyond where the top of your triangle will be. It’s important to make it as close to vertical as possible.

 

6. Take your ruler and run it from one end of your original line, adjusting its angle until it crosses the feint line at exactly the 5cm mark. Draw in the second side of your triangle.

 

7. Draw a line from the top point to the other bottom corner of your triangle (it should also be 5cm long).

 

8. Cut out your triangle and use it as a template to draw and cut out 19 more triangles.

 

9. Take 4 of the triangles and arrange them into a larger triangle. Use tape to stick them together.

10. Repeat with another 4 triangles.

 

11. Join the remaining 12 triangles into pairs.

12. Taking three of the pairs, attach them to one of the larger triangles in this pattern.

 

13. You’ll notice that there are three ‘gaps’ in this flat shape. Close each of these ‘gaps’ by sticking the two edges together.

 

14. You will end up forming a bowl-like 3D shape.

 

15. Repeat steps 12 to 14 with the remaining large triangle and three pairs.

 

16. It’s easiest to add the numbers for your die at this point, though you can wait until the end if you prefer.

 

17. Grab a pen and draw in the numbers according to this pattern which nicely spreads out the numbers. Your die won’t be highly accurate because its weight won’t be distributed evenly but using this number pattern is a step in the right direction!

 

18. Start to assemble the icosahedron by joining the edges of the triangles numbered 3 and 19.

 

19. Working methodically, slowly stick the two halves of your shape together using sticky tape.