Write a third order quine
Python -&gt; Perl -&gt; Ruby, 48 characters
Adaption of my previous answer. Running
s='print q&lt;puts %%q{s=%r;print s%%s}&gt;';print s%s

with Python generates this Perl snippet
print q&lt;puts %q{s='print q&lt;puts %%q{s=%r;print s%%s}&gt;';print s%s}&gt;

which generates the following Ruby code
puts %q{s='print q&lt;puts %%q{s=%r;print s%%s}&gt;';print s%s}

which then prints the original Python snippet:
diff -s &lt;(ruby &lt;(perl &lt;(python thirdorderquine.py))) thirdorderquine.py 
Files /dev/fd/63 and thirdorderquine.py are identical