There should be three tall floats, each of which should extend
into the next column (F2, F3) or into all columns (F1).
First
First
F2
First
First
F1
First
First
First
First
First
First
Second
Second
F3
Second
Second
Second
Second
Second
Second
Second
Third
Third
Third
Third
Third
Third
Third
Third
Third
Third