Devices in Meditation
In kammattana, it is permissible to use certain devices, such as the earth or color kasina, as focal points for the attention. A candle flame, a hole in the wall, or some metal object can also be used, and the method of using them is found in the Pali texts and the Visuddhi-magga. In the texts themselves it is to be noted that the Buddha gave objects of meditation to disciples in accordance with their individual characteristics, and his unerring knowledge of the right technique for each came from his insight into their previous births.