In a large bowl, using a mixer, cream butter and sugars until fluffy. Add egg and almond extract, beating until creamy.
In another large bowl, sift flour and baking soda together. Add walnuts and blend well; then, stir flour mixture into creamed mixture, mixing until a soft dough forms. Cover and chill 1 hour.
Preheat oven to 350 degrees. Grease cookie sheets.
On a lightly floured surface, with a floured rolling pin, roll out dough to 1/4-inch thickness. Draw a simple light bulb pattern on plain paper (see image below for shape), then cut out with scissors. Place pattern on dough and use a sharp knife to cut out cookies. Transfer to prepared cookie sheet. Using a drinking straw, make a hole at the square end of cookie. Bake in preheated oven 8 to 10 minutes or until cookies are light brown. Cool completely on wire cooling racks.
In a large bowl, stir sugar and milk until smooth. Divide icing evenly into 5 small bowls. Leaving 1 portion of icing white, tint remaining bowls green, red, yellow and blue. Spread icing over each cookie down to squared bottom. Allow icing to harden and set. String black licorice strings through holes to resemble string of lights. Store cookies in an airtight container and assemble as used. Makes 24 cookies (4 “strings of lights”). Enjoy!