Cut out a rectangle of acetate to the required size. Pipe fine lines of chocolate across the length of the acetate, ensuring that you have a margin of 1cm (½ inch) on the left-hand side. Join the lines together with chocolate at the left-hand side.
Create a hoop with the acetate ensuring that the right-hand side of the acetate pushes into the join on the chocolate lines. Place into a 5cm (2 inch) ring mould to set.
For a 3-line hoop: cut the acetate to 4 x 16cm (1½ x 6¼ inches) and pipe 3 fine lines across the length.
For a 7-line hoop: cut the acetate to 8 x 16cm (3¼ x 6¼ inches) and pipe 7 fine lines across the length.
Patisserie by William and Suzue Curley, £40 Jacqui Small