Symmetrical or Mirrored Fingers
Ulna Dimelia has a unique condition that can affect anyone, although it is very rare. The disorder features mirrored fingers. The patient’s hand has eight fingers, four facing the other four, hence the name “mirrored fingers.”
Source: Reddit
Before knowing that it is a disorder, some people think that the patient is holding hands with themselves. You could also believe that it is two people high-fiving. It’s amazing to see but must be difficult to live with.