t{r<Enter>           /* replace space with new line */
/---<Enter>
3r=                  /* replace --- with === */
n                    /* advance to next match */
.                    /* repeat */
r<Escape>            /* cancel, should not alter text */
n                    /* advance to next match */
v2e                  /* select something in visual mode */
r<Escape>            /* cancel, should not alter text */
r=                   /* replace selection */