Turn signal indicator 64 Barracuda- help me understand

Electrical Accessories & Service (Session 207) from the 1965 Master Technician's Service Conference

The schematic they use works like this:
The portions in yellow represent the moving brass contacts in the turn signal switch.
All three contacts move together when the signal lever is moved.
The black circles are contact points that do not move.
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For example, left turn signal.
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Current flow represented in orange arrows.
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