Every merge goes back one generation. Two parents, four grandparents, eight great-grandparents. The 2048 tile is eleven generations back.
Arrow keys or swipe. Empty tiles show the generation until you add faces or names.
Add each person on their own. Any two tiles from the same generation merge, so Mom can match Dad or another Mom. The new tile is a random face from the generation before. You don't need everyone: each generation draws from whoever you've added, and names and dates work when there's no photo.
This clears every photo, name and date from this device. It can't be undone.
Drag to position. Fill the oval with the face.