“…This model has been tested in several ways by many investigators: the 3-and 4-point experiments (Hardy, Rand, Rittler, Blank, & Boeder, 1953;Higashiyama, 1976;Indow, Inoue, & Matsushima, 1962a;Zajaczkowska, 1956b), the alley problem (Hardy, Rand, & Rittler, 1951;Indow, Inoue, & Matsushima, 1962b;Ishii, 1972;Shipley, 1957;Zajaczkowska, 1956a) and examinations concerning the axiom system (Foley, 1964(Foley, , 1972.…”