What Watch draws synastry charts in the same wheel, but in different colors. In the example shown on the left, Jupiter is in conjunction with the other person's South Node. Farther down, you can see the Moon conjunct the other's Sun, Neptune near the other's Pluto, and Pluto near the other's Uranus, and so on.

Conjunctions are always easy to spot. Higher aspects are more difficult to trace – What Watch offers two techniques for this purpose: aspect lines, although they tend to be confusing in synastry, and the harmonic aspectarian which can prove its strengths here. As interaspects between two charts tend to be very numerous, it's particularly difficult to find some traces of order in chaos.

Aspects
Look at the 12th harmonic, a part of which is shown in the inset of the graphic. It shows planets that are in aspect by any multiple of 30 degrees. You find that the Sun and Neptune are in contact, as well as the other person's Mars. The other's Pluto is also very near (about one degree away).

If you look at the chart itself, you see the black Neptune and the black Sun forming a square, black Neptune and red Mars a quincunx and red Mars and the black Sun a sextile. So the other person's Mars – and Pluto – activate the natal Sun/Neptune square. Look at each harmonic and you'll find all places in the chart activated by the other person.