Curvature Cones

Hello Guys,
I am new in Rhino and Grasshopper. I was trying The Curvature Cones Definition of [FORMul[a]RCH] http://formularch.blogspot.com.tr
I do have a difficulty to create a reference curved surface to get the proper result of the definition. Could you please help me to figure out creating a wavy curved surface to run the definition?
Thank you,