In the Jacquard loom mechanism, what did a hole in a specific position on a card allow?

Answer

A corresponding needle to pass through and control the harness lift

If a card had a hole at a certain position, the associated needle could pass through it, enabling the corresponding harness to lift the necessary warp thread for that row of the pattern.

In the Jacquard loom mechanism, what did a hole in a specific position on a card allow?
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