What is the meaning round beads around the neck of Sha Wujing?
Today the beads are generally used for counting the breaths, however there is also a use for divination. In the latter each bead is assigned a meaning according to the breakdown of sense experience (vedana) as follows:

The six senses (eye, ear, nose, tongue, body, mind) X pleasant, unpleasant, neither-pleasant-nor-unpleasant
Bound up in the worldly = 18 +
Not bound to the worldly = 18 = 36
X Past, Future, Present = 108.

So bead #1 = past pleasant sensation down-bound to the world related to the eye

When asked a question the diviner finds the bead most appropriate to the question and visualizes (from his associations with that sense-experience) and interprets to attain an answer.