Optical illusions images PowerPoint version

Natural beauty
The eye says it’s a flower, the brain thinks it’s a face. Carefully positioned images can cause
discrepancies between the actual image and the perception created by the brain.
Credit: Tom Wigley/Flickr, CC BY-NC-SA 2.0.
When the world was flat
This garden in Paris is made up of grass at different heights and white lines. The area is oblong in
shape, but from one angle it looks like a sphere.
Credit: Jeff Hester/Flickr CC BY-NC-SA 2.0
Going up?
Obscured horizons and the contrasting slopes of the landscape and trees often cause people to
lose their bearing on this downwards ‘gravity’ hill.
Credit: Ray/Flickr, CC BY-NC-ND 2.0
I didn’t use Photoshop
A photo of the whole monitor is taken with a hand in front of the screen, and is then set as the
background on the monitor. The note is then opened over the top of the new background.
Credit: Evan/Flickr, CC BY-ND 2.0
Spiralling snakes
This image appears to be moving; the brain detects movement, but this is actually triggered by
black-and-white edges, through the use of curvature, colour and shape.
Credit: Roman Soto/Flickr, CC BY 2.0
Black or White?
Figure–ground perception is the tendency to simplify an image into its figure (i.e. its main subject)
and its background. Whether you perceive black or white as the figure determines what you see
(i.e. vase-like columns or men talking).
Credit: Sha Sha Chu/Flickr, CC BY-NC-SA 2.0
Moving Triangles
The lines running from top to bottom appear tilted but are in fact vertical. Certain shapes and
colours cause the brain to perceive movement in some situations, a phenomenon called retinal slip.
Credit: ClintJCL/Flickr, CC BY-NC-SA 2.0
Our house
Although this room appears to be cubic, it is actually a trapezoidal shape. The woman is actually
standing much closer to the camera than the man.
Credit: Ian Stannard/Flickr, CC BY-SA 2.0
Could you live in this?
Two walls placed at very specific angles create what appears to be a complete building from a
particular viewpoint.
Credit: Thom Watson/Flickr, CC BY-NC-SA 2.0
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