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## 'Make Your Own Pencil Case' printed from http://nrich.maths.org/

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Would you like a personalised pencil case which is exactly the right size for the number of pens, pencils, etc, you generally carry around?  Then make your own!

You'll need to think through some initial questions before you start planning your design:

• How long is the longest pen, pencil, ruler or other object you might want to carry in it?
• How many pens, pencils, etc, do you want to carry about?
• If you bunch then all together, and measure round them with a piece of string, what diameter pencil case do you need?

When you've decided on the dimensions of your pencil case, have a think about what shape would be a good idea.  You may well decide that a cylinder, cuboid or triangular, hexagonal or octagonal prism would work well.

What does the net of the shape you want look like?

• How many separate pieces do you need?
• What shape is each piece?
• Which sides need to fit together?

Try modelling the net of your pencil case with scrap paper, folding the paper net into shape and sticking it together with sellotape.  Does it work?  Is it the right size for your pens and pencils?

Once you're happy with your paper prototype, you need to decide what materials you will use for the real thing:

• Does it need to be a rigid material or could you use recycled fabric?
• Will you need to alter the measurements in your design to use the chosen material?
• Do you want the same material for all the pieces, or could the ends be made of something different from the rest?
• How will you stick or fasten the pieces together?
• How will you do up the pencil case?
• Do you want to put a design on any of the pieces before making up the pencil case?
• How will you ensure your pencil case stays shut?