A square with four quarter circles of which the intersection points are the vertices of a yellow quadrilateral. What fraction of the total area is yellow?
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Solution
The yellow fraction is 2-√3.

Poem
Square eyes
May be some people scream
If you look to much screens
A very strange eye contact
With pictures sometimes blue
Or in colours
A lot of pixels
You think no solitude
With all your screens
A virtual world with social networks
But
Less contacts
Less friends
Less love
