To make the avocado shamrocks, slice an avocado in half lengthwise. Twist both halves to separate, and carefully remove the skin and pit. Slice each half of the avocado in thirds lengthwise to make planks. Use the daisy or shamrock cutter to cut out shamrocks. If cutting out daisies, use a sharp knife to trim triangles from the bottom of the daisy to create a stem.