Just as the Mitchell movement can be extended in length by using the roving board movement, so can the Howell. The major difference is that the Howell does not have the same ease of use of the orderly movement of the roving board.
In the simplest case (the 4 table Howell) consider the two following movements that have the same starting positions.
Board Sets 1 2 3 4 5 6 7
Round 1 8-1 5-4 7-2 6-3
Round 2 8-2 6-5 1-3 7-4
Round 3 8-3 7-6 2-4 1-5
Round 4 2-6 8-4 1-7 3-5
Round 5 3-7 8-5 2-1 4-6
Round 6 5-7 4-1 8-6 3-2
Round 7 4-3 6-1 5-2 8-7
If each vertical column of this expansion is considered as an extra set of boards in the first movement, then it can be readily seen at which tables the extra set of boards is to be placed on which rounds. Set 1 goes to table 1 on round 1, displacing set 1 of the original set of boards (pairs 8-1). Table 2 on round 4 displacing set 7 (2-6). Table 3 on round 6 displacing set 4 (5-7). Table 4 on round 7 displacing set 6 (4-3). Column 2 of the second movement can be used to determine the second roving sets movement, and so forth. More than 2 roving sets would be unusual. For the 8th round the seating positions would be as under the first column of the second movement. The pairs play the boards that were displaced on the round when they previously met. For the 9th round column 2 is used, and so on.
