A mandala is a model of the universe arranged for spiritual exercise, and visitors still feel something like enlightenment on climbing up to the open levels and seeing the distant hills like still another ripple of human existence. Borobudur's name seems to be derived from an expression recorded in two inscriptions of the time and found locally, Bhumisambhara-bhudhara, which means, The concentric structure, like that of mandalas, Borobudur seems to be modeled on a Tantric (Northwest Indian) Vajradhatu, or Diamond World, mandala, for the ten concentric galleries and the five ballustrades bearing niches for the Buddhas below the circular terraces of stupas are laid out in that pattern, as can be seen from five principal Buddhas identifiable from their mudras, or gestures: Center, Vairocana, or Buddhas here are portrayed Dharmacakra mudra, (right thumb touching left middle finger), symbolic of the Buddha's preaching his first sermon. Then on the first four ballustrades: East, Aksobhya, Bhumisparsa mudra, (right hand palm down resting on the knee), symbolic of sacrifice. South, Ratnasambhava, Vara mudra (right hand held palm up), symbolic of charity. West, Amitabha, Dhyana mudra (both hands on lap, palms up), meditation. North, Amoghasiddhi, Abhaya mudra (right hand up, palm facing out), eliminating fear. Fifth ballustrade, all around. Vitarka mudra (right hand up, thumb and left forefinger touching), symbolic of preaching. This anomalous style is a difficulty for the interpretation of the architecture as a conventional Vajradhatu, or Diamond World, mandala, for in that tradition there is no sixth Buddha. But mandalas are found in almost infinite variations. The galleries provide a complete education in the doctrines of Buddhism. At the foot (now hidden by a supplemental foundation) is a retelling in sculpture of the Mahakarmavibhangga, the doctrine of worldly desire and the causes of good and evil. In the first gallery is told the Lalitavistara, life of the Buddha from birth to his first sermon at Benares, and the Jatakamala, his former lives. (There is no interest in the Buddha's subsequent life and eventual attainment of nirvana, since by his first sermon he had discovered everything needful for the compassion of a Bodisattva.) Then in the upper galleries is told a long story, the Gandavyuha, of an ordinary mortal, Sudhana, son of a merchant, in search of enlightenment. Thus the pilgrim gains a complete perspective on life, from desire to the renunciation of desire.