I have a square table-mat made from rope that spirals from the centre. The mat is a 14 centimetre square. The rope is 2 cm wide.

How many centimetres of rope will I need to make another mat just like it?

(Hint: Use some small grid paper and colour the squares to work out how the rope fills the space.)

How much rope would I need to make a 12 cm square, or a 16 cm square? Is there a quick way to work this out?