/usr/lib64/tcl8.6/Tix8.4.3/bitmaps
Edit: /usr/lib64/tcl8.6/Tix8.4.3/bitmaps/plus.xpm (200B)
/* XPM */
static char * plus_xpm[] = {
"9 9 2 1",
". s None c None",
" c black",
" ",
" ....... ",
" ... ... ",
" ... ... ",
" . . ",
" ... ... ",
" ... ... ",
" ....... ",
" "};