I used oddments of DK yarn, in six colour families, to make the mitred squares for this rounded cube.

Shapes like this always deform and try to make themselves round unless they have some kind of stiffening. This one measures about 128 cm (50”) round which is a little strange as each square only seems to measure about 28 cm (11”). The calculations I usually use for garter stitch tell me that each square would be a little under 25 cm (10”) when laid flat.