I want to get the following table:
+---+---+---+
| | b | c |
| +---+---+
| a | | c |
| + b +---+
| | | c |
+---+---+---+
but I can't seem to make it happen. The closest I got was with the following:
.TS
tab(^) allbox;
l l l
^ l l
^ ^ l.
a^b^c
^b^c
^^c
.TE
Which produced the following table:
+--+---+---+
| | b | c |
| +---+---+
|a | b | c |
| +---+---+
| | | c |
+--+---+---+
The following seems to have done the trick.
.TS
tab(@) allbox;
l l l
^ l l
^ ^ l.
a@b@c
@b@c
@@c
.TE
Something in the tools I used seem to be confusing the separator ^ and the vertical span format.