Missouri Star block pattern tutorials are available on QuiltersCache.com and CivilWarQuilts.Blogspot.com. QuiltersCache.com provides the pattern template and instructions for paper-piecing 12-inch blocks and for making a quilt from the blocks. CivilWarQuilts.com's instructions are for an 8-inch block, with a variation for smaller blocks.
To piece a Missouri Star quilt block, get light, dark and medium fabric. For an 8-inch block, cut four 2 1/2-inch squares of light fabric and two 3 1/4-inch squares each of the medium and dark fabrics. Cut the medium and dark squares into four triangles each by making two diagonal cuts. Next, do the same to one 5 1/4-inch square of the light fabric. From the dark fabric, cut two 2 7/8-inch squares; cut each of these once diagonally to make two triangles from each square. Cut one 3 3/8-inch square of the medium fabric.
Stitch the long side of each triangle from the dark 2 7/8-inch squares to each side of the medium 3 3/8-inch square. This makes a larger square, which forms the center of the star. Sew together the shorter sides of one medium and one dark triangle from the 3 1/4-inch squares to make larger triangles. Repeat for all pieces of this size to get eight larger triangles. Sew the long side of each larger triangle to each short side of the light triangles from the 5 1/4-inch square. This makes four rectangles.
Attach two of these rectangles to opposite sides of the center square, with the light fabric facing outward. Add a 2 1/2-inch light-colored square to each short side of the remaining rectangles to make strips. Finally, attach each strip to the long side of the center square strip. Position the outer strips so their triangle points face outward, creating the star.