Scale provides visual cues that help make sense of an image. Remove those cues and the image becomes ambiguous. Fractals fool the eye because they appear almost the same at different levels of magnification. The structure of a fern frond repeats the structure of the whole plant.
Or sometimes little things look like entirely different bigger things. Examining a driftwood log, I found miniature landscapes that bore no resemblance at all to the log itself: a sloping plain ending in a wind-eroded cliff; a dry riverbed meandering through a scoured desert.