A coverage map that's really about the gaps

Held up flat, a near-black tee printed in red and white: five circles, different sizes, overlapping. Where two or more overlap, the shape is filled solid. Where only one reaches, it's left open. Between them, three small gaps sit uncovered, and nothing draws a line around the group as a whole.

Anyone can see where the coverage is. The diagram exists for the three places it isn't.

What do the five overlapping circles represent?

Five separate sources, each with its own reach, drawn together so the reader can see where those reaches overlap and where they don't.

A single circle only tells you about one source. Put five down at their real positions and sizes and a second layer of information appears for free — not from any new circle, but from where the existing ones happen to cross. That's the actual reason to draw five circles instead of listing five numbers: a table of ranges can't show the shape a gap takes, and this diagram's whole job is showing exactly that shape.

Why fill the overlaps and leave the single coverage open?

Because the two areas answer different questions, and the fill is doing the sorting instead of a legend.

A solid area says: covered twice over, redundant, safe to assume nothing gets through. An open area says: covered, but only once, reliant on a single source doing its job without fault. Leaving single coverage open rather than filling it the same way keeps that distinction visible at a glance, the same logic a chart uses when a full tick and a half-mark aren't drawn the same weight because they aren't making the same claim. The gaps, filled with nothing at all, are then the one state left that reads as different again.

What makes the gaps convincing rather than arbitrary?

Placing them where five real circles at real sizes would actually leave a hole, not wherever looks good in the composition.

Five identical circles arranged symmetrically leave symmetrical gaps, which reads as decorative rather than surveyed. Different radii, placed off any obvious grid, produce gaps with irregular shapes and different sizes — one a person could stand in comfortably, one barely wide enough for a doorway. That irregularity is what makes the diagram read as somebody's actual measurement rather than a pattern generated for its own sake. A neat, evenly spaced ring of five equal circles would be faster to draw and instantly less believable — it would look like a diagram made to illustrate the idea of coverage, not one made from a site somebody actually walked.

Does a diagram like this reference real jamming technology?

No — the circles show a generic idea of overlapping range, not a specification for building anything.

Nothing about five overlapping shapes ties to a particular system, frequency or manufacturer; the geometry of overlapping coverage is the same whether the five sources are radios, lights or garden sprinklers. If a design wanted to reproduce a specific device's real published range or a manufacturer's own coverage chart, that chart belongs to whoever measured and published it. This one is invented, which is also why the gaps can sit exactly where the design wants them.

Does the same diagram work for other kinds of coverage?

Any set of overlapping ranges produces the same read, whichever five things are doing the reaching.

Wireless routers in a building, lighthouses along a coast, patrol routes through a district, sprinkler heads across a lawn, market stalls competing for the same passing footfall. What stays constant is the logic, not the subject: fill where coverage doubles, leave single coverage open, and let the gaps fall out of the real geometry rather than drawing them in on purpose. A beam sweeping a fixed arc has the same blind-angle problem in miniature — one source, one gap, the same reasoning at a smaller scale.

Who would actually draw a map like this?

Whoever plans to make use of the gap, not whoever built the coverage.

Nobody running five sources at full function needs a diagram of their own weak points — they already know where the sources are. A map this precise about three small uncovered spaces is drawn by somebody working out where to stand, which is the diagram's real authorship question: a document made from outside a system rather than inside it, in the same way a location only means something once it's pinned against everything around it.

Does it print well?

Yes, especially without an outline holding the group together.

Flat fills with hard edges are exactly what circles want on fabric — no gradient falling off toward the rim, no shading to suggest depth a two-colour print can't render anyway. Leaving the whole group without an outline is worth keeping: a drawn border around the five circles would read as a frame around a diagram, where the bare shapes read as the actual coverage, floating on the shirt the way it would on a real plan. Red for the overlaps, white line work for everything else, is enough.

How do I get one made?

Describe the coverage at JustOG — how many sources, how they overlap, and where the gaps fall. Pick a direction, drag the crop frame, see it composited on the real garment, and it's made to order and shipped.

Designs other people have published are in the shop.

Three small gaps between five circles, and somebody already knows which one they're standing in.