Free Triquetra Grid Generator

Each pair of the three arcs overlaps in a pointed lens, which is a vesica piscis — the figure the vesica piscis tool draws on its own. The triquetra is the figure those three lenses make when the three circles they come from are arranged symmetrically, which is why it turns up in the same architectural contexts as the vesica: window tracery, arch heads, panel fills.

The overlay draws no over-and-under. A drawn or carved triquetra is usually an interlace: the three arcs weave, passing alternately above and below each other, and that alternation is what makes it read as a knot rather than as three overlapping loops.

This draws the path — the geometry the interlace follows — and leaves the weaving to you. That is the right form for a construction layer: you lay it down, then ink or carve the crossings with the correct alternation, and the underlying arcs stay exact while you do. An overlay that pre-decided the weave would be harder to work over, not easier.

It is also the honest form. Any two of the three arcs cross twice, and there are six crossings in total; a genuine alternating weave over them is a decision about which strand is on top at each, and there is more than one valid answer. Drawing the path leaves that decision where it belongs.

Triquetra-like three-lobed motifs appear in Iron Age European metalwork and on Germanic and Norse objects well before the Insular manuscripts. The version most people picture — clean, closed, often enclosed in a ring — belongs to the Insular tradition of the seventh to ninth centuries, alongside the interlace of the Book of Kells and the Lindisfarne Gospels, and to the stone crosses of the same period.

Its use as a specifically Christian trinity symbol is documented but later and partial; the motif also appears in contexts with no such reading, and the hexagram generator carries a comparable history of later readings attached to an older figure. The modern name "trinity knot" projects one interpretation backward onto a much broader body of use. As with the hexagram, a figure this easy to construct recurs without needing to be borrowed.

For carving and cut work, export SVG. Everything in the figure is arcs, and a raster version of a curve becomes a staircase at any real cutting size — most obviously at the three tips, where the curvature is highest and the eye is most attentive.

For inked interlace, export the path at low opacity and draw the weave over it. The construction-step control is worth using here: watching the three arcs go down one at a time makes it obvious which strand is which, which is exactly what you need to keep straight when you start deciding crossings.

And a note on the ring. Enclosed and open triquetras read differently on the same object: the ring closes the figure and makes it a badge, where the open form reads as ornament that could continue. Both are traditional. The overlay draws the ring at 1.12r, just clear of the lobes, because a ring that touches them turns four separate elements into one ambiguous outline at small sizes.

The triquetra overlay page works through the surviving examples, beside the rest of the other sacred-geometry figures. Three things vary between historical triquetras and all three are worth knowing before you copy one. The first is whether the ring is present, which changes the figure from ornament to badge. The second is the strand width relative to the radius — Insular manuscript versions are typically thin, while carved stone versions are much heavier because a thin strand does not survive weathering.

The third is the lobe proportion, which is the one this overlay fixes. Some drawn versions push the arc centres further out than half a radius, producing longer, narrower lobes and a more pointed figure; others pull them in for a rounder, fatter knot. Both are found historically, and the version here sits at the centre of that range.

If you are matching a specific piece, fit the overlay to it and see where the lobes disagree. Consistent disagreement means the original used a different centre offset, and once you know which way it went you can compensate by scaling the overlay non-uniformly — or simply accept it as the piece's own character and draw the rest to match.

A note on line weight, because it decides more about this figure than the geometry does. The three lobes meet at six crossings, and at every one of them two strokes converge at a shallow angle. Set the weight too heavy and those meetings fill in solid, turning six crossings into three blobs and losing the knot entirely — which is the single commonest failure in a printed or embroidered triquetra.

The safe test is to view the figure at the size it will actually appear, not at the size you are drawing it. A weight that reads as crisp at screen scale is frequently three times too heavy for a pendant and half what a carved version needs. The overlay's own line-width control makes that a five-second check, and it is worth doing before the geometry is committed rather than after.