Geometry Mystery

 

You have a circular design here, one we'd call a Mariner's Compass

How are you going to set the circle into a quilt?

We'd draft 4 corner shapes to fit it into a square.

Circular designs can be pieced into a square or appliqued.

And that's how we'd do it.

Circle from our Southern Spin BOM last year here.

Becky Brown pieces the center in last...

and then pieces the circle into a square.

But in the past...

Rhode Island project & the Quilt Index, about 1830.

Stella Rubin's inventory

Marquette Regional History Museum Collection

Michigan project & the Quilt Index

They pieced the rather difficult-to-piece circles into rather

difficult-to-piece sets.

When chintz-scale florals were the fashion one sees sets of chintz florals.

As taste changed to favor red and green solids and small-scale prints

the circles were sometimes pieced into white shapes ....

What would you call those white shapes?

You would think that a common shape 

completing a circle into a flat pattern would

have a name.

A catchy name. But NO!

The best I can come up with is Quadrilateral Interstitial shape

(mostly discussed in atomic structures.)

Even snappier a term is Octahedral Interstitial Site if it has 8 sides.

A shape you see in setting these circular designs.

Then there is the more elusive Hexagonal Interstitial Shape

I found one daring quiltmaker

My resident geologist says in a rock the shape would be a pore,

the space between the other shapes.

That's a quadrilateral interstitial site. Four sides, not 8. Not going to catch on.

Years ago quiltmaker and graphic artist Jean Mitchell called this shape a Squeezed Square when we were cataloging Carrie Hall's quilt blocks and I guess that is going to have to do as "Octahedral Interstices" is never going to catch on.

I used the term in Clues in the Calico in 1979

Pat Crews and the Nebraska project used "Squeezed

Square" to describe the interstices in this end-of-the-19th-century

Mariner's Compass.

Squeezed Square hasn't caught on either.

But it beats Octrahedal Interestice or Pore.

Square shape with concave sides????

UPDATE! JoAnn tells us that Paper Pieces will sell you templates for this shape & they call them Clam Points.