Sandbox
col 1
col 2
col 3&4
row a
:2 a1-b1
:3_ a2-c3
a4
row b&c :2-
b4
c1
c4
row d
d1
d2
d3
d4
col 1
col 2
col 3
col 4
row 1
1
2
3
row 2
col span
end
row 3
1
2
3