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Another strategy is to reverse the normal scanning direction. If you naturally look from left to right, try right to left. If you normally start with the top half, begin at the bottom. Changing direction disrupts habitual eye movements. The same scene can suddenly feel less familiar.
Turning the image slightly can sometimes help as well if the viewing platform allows it. Rotation makes familiar objects temporarily harder to recognize. That sounds counterproductive, but it can reduce the brain’s tendency to label the background automatically. Hidden geometric shapes may become more noticeable when the normal scene loses some of its meaning.
Another approach is to temporarily ignore color. Concentrate only on edges and boundaries. Follow every place where one shape meets another. This can expose objects whose color has been perfectly matched to their surroundings. Camouflage based on color becomes weaker when the viewer focuses on geometry.
The reverse strategy can also work. Ignore shape and look for subtle color differences. A hidden object may follow the outline of a nearby feature while having a slightly different tone. Small variations can become more noticeable when the viewer deliberately stops asking what each shape represents. Pure visual comparison can sometimes succeed where object recognition fails.
Lighting plays an important role too. Bright regions naturally attract attention, while darker areas receive less. A puzzle designer can therefore place a hidden detail near a strong highlight and rely on contrast elsewhere to draw the eye away. Looking immediately beside the brightest parts of the scene may reveal areas previously ignored.
The same is true of visual centers. Most viewers initially look near the middle of an image. Hidden objects placed closer to edges may receive much less attention. Corners and margins should therefore never be skipped. The area near the border of the picture can be surprisingly productive.