Frets

\draw[thick,darktan](-.42,-.75)--(.42,-.75)
                    (-.44,-.55)--(.44,-.55)
                    (-.43,-.35)--(.43,-.35)
                    (-.42,-.15)--(.42,-.15)
                    (-.41,.1)--(.41,.1)
                    (-.41,.4)--(.41,.4)
                    (-.4,.75)--(.4,.75)
                    (-.39,1.16)--(.39,1.16)
                    (-.38,1.6)--(.38,1.6)
                    (-.37,2.05)--(.37,2.05)
                    (-.35,2.5)--(.35,2.5)
                    (-.33,2.96)--(.33,2.96)
                    (-.32,3.4)--(.32,3.4)
                    (-.32,3.85)--(.32,3.85)
                    (-.31,4.3)--(.31,4.3)
                    (-.29,4.75)--(.29,4.75) ;