It would appear to be the zigzag shape of this block, which creates the "windmill" effect via imagined radio waves, instead of the turning of the design, as one might expect (see illustration left). There are plenty of pinwheel type patterns which do that, but this is not one of them. Here we have the typical radio wave emblem, extending out via long lines (see the tiling below).
The basic, underlying 10 x 10 drafting pattern has many other incarnations, the most well-known is probably ARABIC LATTICE. In addition there are a number of variations on the Radio Windmill design itself, depending on the size of the grid. In some versions the off-centered square is smaller, in other versions larger. Barbara Brackman's ENCYCLOPEDIA OF PEICED QUILT PATTERNS has an interesting collection of variations for comparison, see blocks #2554 through #2569 (p. 317).
Jinny Beyer's QUILTER'S ALBUM OF PATCHWORK PATTERNS repeats the block as a four-patch (p.144-5). The design was reproduced in the Kansas City Star in 1941, when the wireless radio was all the rage, transforming entertainment and lifestyles in the same way the home computer does today.
Compare at this site with:
DELAWARE CROSSPATCH and DUCK CREEK PUZZLE, also SQUARE DANCE and ENTERTAINING MOTIONS.
And for another exquisitely unusual and colorful 10 x 10 design, see LOCKED SQUARES.