“…The "three mountains" task, in particular, has been fairly extensively 6 researched, though not always with corroborative results (Fishbein, Lewis, and Keiffer, 1971;Lovell, 1959;Shantz, 1971). Other spatial tasks of Piaget and Inhelder that have reappeared in various adaptations and repli cations have been the water level task, the projection of a straight line, and various paper-folding tasks (McGee, 1979).…”