If the hotplate has two spirals of the same power, then it is designed for three heating modes; if two spirals of unequal power

If the hotplate has two spirals of the same power, then it is designed for three heating modes; if two spirals of unequal power, then into four modes. Prove it.

For two spirals of the same power, three modes are possible:
1) one coil is connected:
2) two spirals are connected in parallel:
3) two spirals are connected in series.
For two spirals of unequal power, four modes are possible:
1) the first spiral is connected:
2) the second spiral is connected:
3) two spirals are connected in parallel:
4) two spirals are connected in series.

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