concatenate, compose, covered in a gauze like net
叕 centers on joining or linking things together: concatenating, composing, or connecting. The 'covered in a gauze like net' sense is a rare, specific application of that linking idea, like threads woven into a net.
叕 is a rare character whose exact historical development is uncertain. It visually stacks two 双 (pair) components, which may suggest repeated joining or linking, but this is a modern shape interpretation rather than a confirmed ancient origin.
See two 双 (pair) components stacked: each 双 is a pair of hands (又) joined, and stacking them suggests linking pair after pair, like concatenating or composing a chain.
For テイ, imagine using sticky tape to concatenate the two 双 pairs: tape -> テイ, and the tape joins everything together.