Are all clones created equal? Arrows mark the direction of regeneration, shades mark the regenerated part, and stars mark the retention of memory. (A) Case 1: planaria produces genetic and epigenetic clones upon fission, while brain-encoded memory is erased (‘twins’). (B) Case 2: fission creates different sets of starting conditions to the regenerating fragments and thus making them ‘siblings’. (C) Case 3: the naïve fragment is a descendent of the experienced head fragment which still retains the memory. While similar to case 2, the head fragment in this case remains the ‘parent’ of the tail fragment and does not undergo any major process of resetting of past experiences. (D) Case 4: the organisms that result from fission are truly identical if neuronally-encoded memories are shared between the clones (‘myself’).