Yes, it's triangle time!
Print or trace the block diagram onto foundation paper. Number and cut out the numbered pieces.
If you're not using freezer paper to foundation piece, trace the top and bottom sections of the block onto the dull side of freezer paper.
Cut a 6" x 2.5" piece of main fabric and a 6" x 2.5" piece of background fabric.
Place the bottom freezer paper section on the right side of the background fabric section and, using a disappearing or washable marker, mark the four corners on the fabric. Make sure there's enough fabric around the edges for the seam allowance.
Cut the arc shaped section out of the freezer paper piece. If the top section falls apart, it's OK.
Keep the section you cut out to use later.
Iron the top freezer paper piece to the right side of the background fabric, lining up the corners with the markings on the paper. Cut out along the curve, leaving a seam allowance for turning under. Clip the curve almost to the freezer paper every 1/4" or so.
Place the main fabric piece right side up on the table. Place the background fabric right side up on top of it and baste through all layers.
Turning under the background fabric as you go, reverse applique along the curved edge.
Iron the freezer paper section you cut out and kept back into position.
Cut a piece of background fabric large enough for the top section plus seam allowances.
Cut the small leaf shaped section out of the top freezer paper being careful to leave the rest intact.
Applique the little leaf in main fabric onto the background fabric. Check to make sure that it's not too close to the edge of the fabric.
I used the freezer paper on top method but this leaf is so tiny I'm not sure what the best method would be.
Place the freezer paper section on top of the appliqued fabric, positioning it over the leaf where it should be. Iron the freezer paper onto the fabric.
Foundation piece all the numbered sections.
Trim all seam allowances, including the top and bottom sections, to 1/4".
Assemble the block, referring to the block diagram. I've found that starting from the bottom and checking whether it's straight after each section is sewn on works pretty well.