The lines we added become the edge where two forms meet. These arcs form the sphere the starfish sits on. This work is done with a small cross pein and raising hammer, over a ball stake. It takes several courses to define the ball. To find rescources on fold forming: to the left of these pictures is an Amazon search panel.
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By forging only the folds the folded areas begin to curve. I'm only hammering the fold about 3/4 of an inch in from the fold. The untouched valleys will wrinkle, That's OK we have plans for that area. Work all five folds, anneal, repeat this three or more courses to get a nice curve to each fold. Note I rather like the hammer marks on the starfish I want the marks to be on both the right and left sides of each arm. I use a cross pein hammer for this. Anneal before going to the ball stake. The bowl is developed over a ball stake.
Dividing a circle into five equal parts shouldn't present a large problem. I will frequently attach the paper pattern to the metal. A spray adhesive will work fine for this. The lines will become the folds that create the piece. I'm working 24 gauge copper. That's a 6 inch disk. Close up the folds. This will get us started. Note the related forms fron one of the pics. Note only the folds will be hammered. The valleys do not get hammered.