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ISOFILL: Divide the grid into 9 regions, each containing 9 orthogonally connected cells. All cells in the same region must contain the same digit. All of the digits 1-9 must appear in the grid.

ENTROPIC LINES: Each peach line must contain one low digit (1, 2 or 3), one medium digit (4, 5 or 6) and one high digit (7, 8 or 9.)

THERMOMETERS: Digits along a thermometer must keep increasing as they move from bulb to tip.