Here 3-wire cable is run from a double-pole circuit breaker and split to supply 120 volts to two sets of receptacles. The neutral wire from the circuit is shared by both. This wiring is commonly used in a 20amp kitchen circuit where two appliance feeds are needed, such as for a refrigerator and a microwave in the same location.
Here two receptacles in one box are wired using the device terminals. With this arrangement, if receptacle #1 fails, receptacle #2 may also fail if failure is due to physical damage. However, if the copper tab conductors between the terminals remain intact, even if #1 stops functioning, receptacle #2 will probably still work.
The source hot is spliced to the red wire which is connected to the bottom terminals on the switch at the other end. The black wire is connected to the top terminal on the switch which runs power back to the fan where it is spliced to both the black and blue fan wires.
The black wire is splice to the output on the speed controller and to the black, fan wire at the other end. The red wire is spliced to the output on the dimmer and to the blue, light wire at the other end. The neutral from the source is spliced in the switch box with the white wire, and to the neutral wire on the ceiling fixture at the other end.