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Plot of Nielsen's spiral, also known as the sici spiral.

This picture was created by Jitse Niesen using the following Matlab code:

ts = linspace(0.8, 30, 1000);
xs = 1/2i * (expint(ts*1i) - expint(-ts*1i)); % sine integral
ys = -1/2 * (expint(ts*1i) + expint(-ts*1i)); % cosine integral
plot(xs,ys, 'LineWidth', 2);
axis equal;
axis off;
print -dpng 'nielsen_tmp.png';
system('convert -trim -bordercolor white -border 10 +repage nielsen_tmp.png nielsen.png');

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