No. CXXVI

When the walnuts and cobnuts have been arranged as is shown on the diagram—

they can be shifted so that they stand alternately, by moving two that are close together at a time, in four moves, as follows:—

(1) Move 2 and 3 beyond 8.

(2) Move 5 and 6 between 1 and 4.

(3) Move what are now 6th and 7th in the gap.

(4) Move what are now 1st and 2nd in the gap, and the alternate arrangement is complete.