/usr/share/freemat/toolbox/graph/testtube.m is in freemat-data 4.0-5build1.
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 | % Copyright (c) 2002-2007 Samit Basu
% Licensed under the GPL
t=0:(2*pi/100):(2*pi);
x=cos(t*2).*(2+sin(t*3)*.3);
y=sin(t*2).*(2+sin(t*3)*.3);
z=cos(t*3)*.3;
tubeplot(x,y,z,0.14*sin(t*5)+.29,t,10);
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