New tenants move into a new apartment.
Six rooms are on the same floor, all communicating, as shown in the
The rooms numbers 4, 5, and 6, all facing the
The tenants insisted that the piano and the bookcase should change
Now, the rooms were very small and the pieces of furniture indicated
were very big, so that no two of these articles could be got into any
room at the same time.
How was the exchange to be made with the least