Creating Edges or Grooves on surfaces/Solids

How to create repeating ridges / grooves on the sides of a solid / surface in a loop.
Imagine it to be a letter cutout and along the outer edges there is to be repeating grooves

I would use FlowAlongSrf command to place the ridges or grooves on the solid or the surface. Boolean commands (BooleanUnion, BooleanDifference, etc.) can be used not only on solids, but also on surfaces. If the surface normal directions are correct, the Boolean commands will work well. (Use Dir or ShowDir command to check normal directions.) Boolean commands work best when the ridges and the solid overlap.

can you post an image of what you are trying to create? There are a number of possible workflows depending on your design intent-