Multi-Wheel
Two, three or four charts as concentric rings on one zodiac — a bi-wheel, tri-wheel or quadri-wheel. Each person keeps a ring; the shared band lines their planets up degree for degree, and the URL carries the whole stack.
What a multi-wheel is
A multi-wheel stacks several charts on one zodiac: each chart's planets take their own ring, innermost first, so the same degree lines up radially across every chart. Two rings make the familiar bi-wheel; a third or fourth person makes a tri-wheel or quadri-wheel.
Because every ring shares one zodiac band, a contact between charts reads as glyphs stacked along one spoke. Astrologers draw these to compare a family or a group at once, or to lay event charts over a birth chart; this page draws any two to four birth charts.