Here is a short tutorial on how I made the vase for the corner blocks.
I really love this freezer paper. You can find it here.
I can make appliqué templates out of it and they will hold up to a moderate amount of starching and pressing. I use this for all my larger shapes because you can iron it onto the back of your fabric and it will stay put while you starch your seam allowances.
Trace your vase parts onto the NON shiny side and iron a second one onto the back. Make sure the top piece is stuck to the non shiny side of the bottom piece.
Cut out your shape and iron it onto the back of your vase fabric.
Trim the excess fabric and starch like you normally would.
Here’s the front.
Once everything is dry you can remove the template and use it again.