Comment by mncharity

WebGL's swizzling vector selectors.[1] Where v.x desugars as v[0], v.y as v[1]. Similarly for z and w. Also r,g,b,a. And they swizzle: v.rgb, v.xz, v.zx . So `v1.xy = v0.yx` reflects.

[1] https://www.w3.org/TR/WGSL/#vector-access-expr