So, here I am, snowed in and looking through my vintage cooking pamphlets for doughnut recipes, and I discover that The New Home Cook Book (1926, Latest Revised Edition) offers no fewer than nine recipes for doughnuts.  And one of them (p. 36) goes like this:

Doughnuts.
One cup sugar, one cup milk,
Two eggs beaten fine as silk;
Salt and nutmeg (lemon will do),
Of baking powder, teaspoons two;
Lightly stir the flour in,
Roll on pie board, not too thin,
Cut in diamonds, twists or rings,
Drop with care, the doughy things,
Into fat that briskly swells
Evenly the spongy cells;
Watch with care the time for turning
Fry them brown, just short of burning,
Roll in sugar, serve when cool,
Price a quarter for this rule.

I can’t see any reason not to make diamond-shaped doughnuts, can you?

The New Home Cook Book, 1926