A scribe, twisted scribe, needle, pin or other sharp pointed tool are all perfect for incising lines, or writing in the wax; the line can be filled in (referred to as intarsia; a form of wood inlay)- with encaustic, oil paint, or paint sticks.
Some tools of this nature can be modified by adding a handle to make it more comfortable to use; handles can be salvaged from outmoded tools (like button-hooks), broken tools (like clay tools), or purchased from various companies (like Edward C. Lyons).
