Pair Orbit

Each life is drawn in its own frame, exactly as its own Orbit, so the two shapes are not compared place by place: a dot higher on one side means nothing about the other. What passes between the two people is carried by colour, by the window and by two strips under the drawings.

On a phone the two lives sit one above the other; on a wide screen, side by side. Turning either one turns both.

This is the Match reading (how matches are scored) with two things allowed to move as the years go by:

• what each person holds, read as half the birth chart and half the running luck;
• luck that lands on the other person's spouse palace, the branch of their day pillar.

What lasts longer counts for more. The birth charts' own spouse palaces count 12 points, as they do in the Match reading; a decade luck on the other's palace 8; a year on it, or the two decade lucks meeting each other, 4. With no luck moving, it is the Match reading's own number exactly, and it reads the same whichever of the two is asking.

The drawings open coloured by it, blue above the birth charts' number and crimson below, full at 8 points either way. The window gives the month's number with each reason that moved it, and the day's. The first strip draws it month by month across the years the two share.

This is the app's own construction on a classical habit of timing a bond by the luck. It is a leaning, never a verdict, and it describes two people, one of whom may not have asked.

In step is how alike the two read on one day, measured against random days of the two lives, so 0 is chance. Two people can read alike on a day and still not suit each other, or read nothing alike and suit each other well.

We checked: across ten pairs, in step and compatibility by date did not move together. So the window prints it with the words “Alike is not compatible”, and the second strip draws it on its own, with bands for the years the two decade lucks pair up or clash.

When one person's birth branch sits on the other's helping positions, the noble stars Orbit draws, that person is a noble person for the other: the classical sense of being someone's Gwiin. It can run one way, both ways or neither. Like the noble stars, it is a mark only: no score moves.

• A friend is read from the birth on your own friend list, so nothing in their Orbit is anything you do not already hold. A friend of a friend, whose birth you do not hold, cannot be a partner.
• A well-known person is read from the published date alone, never the hour, as everywhere else in the app.

Which way decade luck turns depends on gender. The first time you open Pair Orbit with a friend it asks once and keeps the answer on your friend list, where only you see it; skip it, and their decades are drawn approximately. Well-known people carry no gender in our data, so their decades are always drawn approximately, and the drawing says so.