Matches  in the shape of a Heart have been inserted vertically in wet clay,  the fire was initiated at one spot and spread in both directions, you can see to the left that they have not met yet.
<a href="//commons.wikimedia.org/w/index.php?title=User:Setsuecia&amp;action=edit&amp;redlink=1" class="new" title="User:Setsuecia (page does not exist)">Set Söderholm</a>
<span class="int-own-work" lang="en">Own work</span>