Here are eight mathematical postcards:
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<A HREF="th-broer.jpg"> The bridges of K&ouml;nigsberg</A><br>
<A HREF="th-firfa.jpg"> The Four Colour Theorem</A><br>
<A HREF="th-knude.jpg"> Viruses and knots</A><br>
<A HREF="th-leopa.jpg"> Animals with a spotted body</A><br>
<A HREF="th-primt.jpg"> Prime and twin primes</A><br>
<A HREF="th-rekor.jpg"> Records</A><br>
<A HREF="th-snegl.jpg"> The Nautilus shell and the golden mean</A><br>
<A HREF="th-solsi.jpg"> Sunflower seeds and Fibonacci sequence</A><br>