How to communicate visually the ability to change columns in a table

Often websites may include functionality that allows a user to select what columns appear in a table. When this occurs, what is the best way to visually communicate this action, so the user both understands it is possible and knows how to perform it?

We are trying to implement this functionality on our site, but we are at a loss for a good way to indicate it. Two icons have been suggested (a pencil and a hamburger) but they are both very general and may not be clear. It's not obvious that this functionality can be indicated with an icon.

Are there any alternatives to this approach?