I.
take a penny.
any penny will do.
it needn’t be a clean penny, shiny and new.
it needn’t be of zinc or copper, nor of wartime steel.
it needn’t be a penny at all, but pennies are useful objects.
take a penny, and a handful more as well, and lay them flat on a flat place.
choose one to be your central penny.
arrange your remaining pennies to circle this chosen center so that
each one touches the central penny’s outer edge and none overlaps.
the greatest number of pennies falling into such a circle
is the kissing number for pennies in two dimensions.
(dimes work, too, and nickels, and quarters, and subway tokens—
or coat buttons or shirt buttons or campaign buttons, all will do—
so long as all your circles are of equal size.)
II.
the kissing number in one dimension is two.
in two, as your pennies demonstrate, the kissing number is six.
it is twelve in three.
in eight dimensions, the kissing number is two hundred and forty.
in twenty-four dimensions, the number is 196,000 and change
(a great deal of kissing in twenty-four dimensions).
in other dimensions, the kissing number is difficult to determine with certainty,
though it is said that in five, the kissing number could well be forty-five.
it is in three dimensions that coping with the kissing number first presents a complex task.
we’re not limited to pennies here, flat in their tidy circlings,
stable in the gravity of their situatings.
here, we have spheres to balance—a central sphere and its twelve bussers
(all twelve kissing in this example),
none of which is permitted to impinge upon any neighboring sphere
except in the most superficial way.
it’s enough to make one wish to possess the skills of a juggler
or a bottle of strong glue to fix the spheres in place.
it’s enough to make one wish for that palmful of pennies laid flat,
or for an existence safely confined to that one dimension
wherein the kissing number is never greater than nor less than two.
(Copyright 2023 by Tetman Callis.)