In case anyone is wondering, there is a pattern for this...It is one of Lisa backporch designs. She has several templates to create curve patterns...this one uses the the 7" and 3.5" templates. Here is her site...I have all the sized templates except the melon template and rainbow template.
http://backporchdesign.com/templates-rulers/
http://shibori-dragon.myshopify.com/...ernoon-delight
She also has videos here is one that she demo for 3 1/2" one...
https://www.youtube.com/watch?v=iosfbWAy_gg
https://www.youtube.com/watch?v=Cu9Y-qfquM0