The balls with embroidered stitching were made according to the principles of “temari” fabrication, by Ingrid Daubechies, Kathy Peterson and Carolyn Yackel. Temari making is a craft of Japanese origin; Carolyn started making geometric temari many years ago, highlighting special symmetry groups. In the process of working on the Mathemalchemy installation, she taught Ingrid and Kathy.
In principle, both the Diverging and Converging Arches have an infinite number of balls. In reality, only a finite number of balls were fabricated, of course — 100 balls for the Diverging Arch, and just 28 for the Converging Arch.
Read Converging and Diverging Ball Arches by Carolyn Yackel
Each of the balls in the Ball Arches has a styrofoam ball at its core, drilled straight through so as to allow the finished balls to be threaded on the Arch support. This central tunnel was lined with a 1/8” wide plastic drinking straw, to protect the styrofoam inside, so it wouldn’t start disintegrating after repeated installations. Around this core, a layer of yarn was wrapped first, at least 1/4” thick, to make it possible to stitch on the balls.
Mari & Temari
For most balls, fabrication did not go past this mari stage. Balls that were designated to become temari were further embroidered in several colors of pearl cotton, contrasting in color with the mari wrap, according to the chosen design. The table shows details of the temari embroidery.
In some cases (balls 3, 13, 19, 41 and 61), the embroidery outlines the edges of the corresponding Catalan solid (imagine it inscribed within the ball); in other cases (7, 17, 31, 59) the faces are highlighted by woven rectangles (7, 17, 31, 59) or triangles (5) framing their edges; in two cases (11 and 29), the faces are highlighted by woven triangles using the midpoints of edges as their vertices. In most cases (all but 13, 41, 61 and 73) the edges defining the pattern are lines of a C8 or C10 temari guideline pattern, also indicated in the table.
When finished, all mari and temari were lightly varnished, and all balls, from the second onwards, were threaded, alternating with much smaller plain wooden spacer balls, onto the steel supports holding up the arches. The first ball, shared between the two arches, was added in front, and hooked onto the steel support mounted within the Doodle Page/Quilt structure. Other support for the arches is from above, via fishing line tethers. The whole support structure was designed and fabricated by Dominique Ehrmann and Stephan LaCourse.