/usr/share/doc/ruby-gsl/examples/gallery/polar.rb is in ruby-gsl 2.1.0.3+dfsg1-1build1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 | #!/usr/bin/env ruby
require("gsl")
phi = GSL::Vector.linspace(0, 2*Math::PI, 200)
r1 = GSL::Sf::sin(4*phi)
x1 = r1*GSL::Sf::cos(phi)
y1 = r1*GSL::Sf::sin(phi)
r2 = GSL::Sf::cos(4*phi)
x2 = r2*GSL::Sf::cos(phi)
y2 = r2*GSL::Sf::sin(phi)
GSL::Vector.graph([x1, y1], [x2, y2])
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