Half Square Triangles Quilt techniques - Pattern are among the most essential skills a quilter can master, offering a gateway to an infinite world of geometric design and creative expression. Known affectionately in the sewing community as HSTs, these versatile units consist of two right-angled triangles joined along their longest edge to form a perfect square. Whether you are a beginner picking up a rotary cutter for the first time or a seasoned artisan looking to refine your precision, understanding how to manipulate these shapes is the secret to unlocking thousands of classic and modern quilt patterns.