Vaisesika Sūtra 5.1.16

इषावयुगपत् संयोगविशेषा कर्मान्यत्वे हेतुः ॥१६॥

iṣāvayugapat saṁyogaviśeṣā karmānyatve hetuḥ ॥16॥

[इषा-अवयु-गपत् (iṣā-avayu-gapat) - simultaneous parts of the arrow; संयोग-विशेषाः (saṁyoga-viśeṣāḥ) - special and distinct conjunctions; कर्म-अन्यत्वे (karma-anyatve) - for difference in movement; हेतुः (hetuḥ) - cause;]

The special and distinct conjunctions of simultaneous arrow-parts cause variation in movement.