## Alice Wilson’s Ahnentafel

An Anhentafel (German for “ancestor table”)  is a scheme for numbering ancestors in strict sequence so that one can easily calculate relationships. The base person is number 1. Each father is assigned a number exactly double that of his child. Mothers are assigned a number equal to that of their husbands, plus 1.

So to navigate through the list: pick any person, note the assigned number, and you can find his or her father by doubling that number. The mother, if known, will be one digit higher and right next door. Likewise, to find anyone’s child, halve their assigned number and ignore any remainder. (Numbers missing from the sequence mean that we haven’t found that ancestor.)[...]