_The Y School_: Unfortunately the program described requires twenty-six classrooms for twenty-one classes of children in addition to the auditorium, play space, library, workshops, etc. No facility during the school day is used more than half the time by the X School. Fortunately the auditorium need be large enough to accommodate only one third of the X School. The same is true of the play space and the special work facilities. There is a great economy in using the facilities named for three periods by alternate groups, each representing one third of the school. But a higher first cost and a greater operation and maintenance cost would be justifiable in all these facilities, including the regular classrooms, if they could be used longer and accommodate more children. Since the X School can use any of these facilities only half of the time, what objection can there be to another school of twenty-one classes using the facilities when the X School cannot use them? On p. 198 is shown a program for such a duplicate school, designated Y. The Y School has the same time as the X School, for both pupils and teachers. Neither school could use any facility any more if the other school were not there, but both schools have better facilities every hour of the day because the other school is there. Forty-two classes of children are thus accommodated in twenty-six classrooms. Instead of building a sixteen-room additional school, with its initial cost of construction, site, janitor service, heating, maintenance, etc., an equivalent expenditure can be made for the permanent improvement and increased operating cost of the twenty-six-room school.