Arcana Coelestia#9660
9660. 'Sixteen bases' means total support. This is clear from the meaning of 'sixteen' as that which is total, 'sixteen' being similar in meaning to 'eight' since multiple numbers have a similar meaning to the simple ones of which they are the products, 5291, 5335, 5708, 7973, and 'eight' means what is complete and what is so in every respect, as shown immediately above in 9659, thus that which is total; and from the meaning of 'bases' as support, dealt with in 9643.
Arcana Coelestia#9645
9645. 'Two bases under one board' means the joining of it to the good. This is clear from the meaning of 'two' as a joining together, dealt with in 5194, 8423; from the meaning of 'bases' as truth through which support is received, dealt with in 9643; and from the meaning of 'board' as good that lends support, as immediately above in 9644.