See a photo step-by-step of doing the double treble crochet stitch. Yarn over hook three times, then insert hook into next stitch. Yarn over hook and draw yarn through stitch - five loops on the hook. Loop yarn over hook and draw through two loops, (there are now four loops remaining on the hook)
Marquetry is the process of decorating an object's surface by cutting and fitting together many pieces of thin layers to create an image. It's often done with veneers, or thin sheets of material like hardwood.
The triquetra is a three part ancient symbol comprised of three interlocked vesica pices, often used to represent people or concepts in groups of three. Also known as the trinity knot and Celtic triangle, it has been found in Celtic art, paganism and also has been used in Christianity.