Blackwork, heart lattice. This technique involves very simple outline stitches, and usually one color, like black, red, or blue. Accents can be added with gold metallic thread, which is traditional. This originated in Elizabethan times to imitate the look of lace on sleeve cuffs, collars, and necklines. It's easy to follow a gridded chart, and use the threads of the fabric as your "grid".