This command will add a cell to a row in a table, breaking the current line if necessary. It is designed to be used at the start of every cell, and as such consecutive <?tbcstrt> commands will break multiple cells. Note that the command will be ignored if it follows any of the following:

When using boxheads, you can specify optional column numbers for the start and end column for the cell. This enables columns to be specified in a non-sequential order and also contain more than one cell which gives rise to the stacking.