Double Guilloche border pattern - Minimum size border pattern.
This shows how small this pattern can go to be set as a border. Using tesserae which are 10mm (7/16") will give you a 24cm x 24cm (9 1/2" x 9 1/2") square to put a centre piece in.
1. Mark a centre point and draw in horizontal, vertical and diagonal lines.
Mark line A on the horizontal to the measurement shown. This will sit between the diagonal lines. Do the same all the way round to create the square.
(B) is the outer line, 14cm out from (A).
2. Mark the first of the single white centre tesserae, (D) on the diagonal lines. This will be 7cm (2 1/4") from the side.
mark the other centre tesserae along the mid line and these will be 9.5cm (3 6/8") apart (E) which will give you, including the corner ones, 5 centre tesserae.
3. And that's it, just draw in the pattern, refer to 4 if you need to. Note, this drawing isn't to scale but drawing 4 is.
This is the minimum size that you can set with this border, you can make it slightly smaller by using just 2 lines of colour tesserae instead of 3, in which case you need to reduce the mesurements accordingly.