<div>This symbol problem represents a heart and contains</div><div>a long solution that leads to the model mate.</div><div>Every piece is needed for the solution!</div><div><a class="pdbkeyw" data-id="S0000345">Keywords: symbol problem</a> (heart), s<a class="pdbkeyw" data-id="S0000140">ymmetrical position</a>,</div><div> <a class="pdbkeyw" data-id="S0000236">asymmetrical solution</a>, flight taking key, <a class="pdbkeyw" data-id="S0001052">selfblock</a>,</div><div><a class="pdbkeyw" data-id="S0000216">switchback</a> (kc6-b5-a4-b5-c6, kb5-c6-b5)<a class="pdbkeyw" data-id="S0000248">,</a></div><div><a class="pdbkeyw" data-id="S0000852">square vacation</a> (d4), <a class="pdbkeyw" data-id="S0000248">model/pawn mate</a>.</div><div>A different animation mode is available at PDB:</div><div>https://pdb.dieschwalbe.de/P1414116.</div><br />