Geomancy, "divination by earth", reads the future from random marks made in sand or soil. It was one of the most popular kinds of divination in the medieval and Renaissance world, from North Africa to England.
The practice began in the Arabic-speaking world, where it is called ‘ilm al-raml, the science of the sand, and was well established by the ninth or tenth century. In the twelfth century, scholars in Spain translated Arabic manuals into Latin, and geomancy spread through Europe, where it was practiced by monks, physicians and philosophers. Cornelius Agrippa and Robert Fludd wrote on it in the sixteenth and seventeenth centuries, and the Hermetic Order of the Golden Dawn revived it in the nineteenth. Its sixteen figures also live on in African divination: in the Ifá of the Yoruba, the Fa of Benin and the sikidy of Madagascar.
A figure is four lines of points, one or two in each line. From the top, the lines stand for fire (the head), air (the neck), water (the body) and earth (the feet). With two choices in each of four lines there are exactly sixteen figures, from Via, one point on every line, to Populus, two on every line. Each has a Latin name, a ruling planet and a character: some are fortunate, some unfortunate, a few depend on the company they keep.
The geomancer holds the question in mind and quickly strikes sixteen rows of marks in the sand without counting. Each row is then counted off two by two: one mark left over makes a single point, none left over makes two. Every four rows give a figure, the four Mothers. Everything else follows by rule.
There is a built-in check. Every line of the sand is counted twice on its way to the Judge, once in a Mother and once in a Daughter, so the Judge always has an even number of points. Only eight of the sixteen figures can be a Judge, and a chart with any other Judge was cast wrong.
The twelve Mothers, Daughters and Nieces can also be laid in the twelve houses of an astrological chart, each house ruling one part of life: money, siblings, home, children, health, partners and so on. The querent is the first house; the thing asked about is the house of its subject. The question is answered "yes" when the two figures perfect, that is, meet in the chart: the same figure in both houses (occupation), one next to the other (conjunction), the two side by side somewhere else (mutation), or a third figure next to both (translation). If they never meet, the answer is no.
Tradition adds a warning: if Rubeus or Cauda Draconis falls in the first house, the chart is not to be judged, because the question was asked at the wrong time or not in good faith.
The marks in the sand are drawn from your browser's cryptographic random number generator, a fair stand-in for a quick hand. Shield and house charts follow the medieval European method. Rulers, signs and elements vary from source to source; this app follows common modern attributions. The meanings, verdicts and advice were written for this app. Use it for reflection and fun, not for decisions that matter.