*Mānasāra*, the most authoritative text dealing with Hindu architecture, iconography as also town-planning, gives us a set of six formulae known as the ‘Āyādi-ṣaḍvarga.’ While dealing with the length,

- breadth
- and circumference or height or thickness
- of any structure, the book gives several alternatives, the right dimension being chosen by the appli-cation of these six formulae. These are āya, vyaya, ṛkṣa yoni, vāra, tithi and aṁśa.

These names represent well-known groups of objects that always follow a certain serial order. For instance, vāra represents the group of seven days of the week. Ṛkṣa represents the group of twenty-seven nakṣatras (star-groups).

Each one of these formulae has already been determined by the text itself. The suitability of a dimension is checked by the remainder left after the application of the concerned formulae. For example, if the height of a proposed new building is to be determined from among the several alternatives suggested by the work, the vāra formula (C x 9∕7) is applied, C standing for the height.

If the remainder is 4, it indicates the fourth day (Wednesday) of the week, considered to be auspicious. Then the measurement chosen is right.