Square Dance
https://www.dwitter.net/d/15182
c.width|=0;with(x)for(globalCompositeOperation="difference",k=81;beginPath(p=1.5708),k--;fillStyle=`hsl(${t*9} 99%60%`,fill(),t=-t)for(j=4;j--;arc((k%9)*w,(k/9|0)*w-60,w,q=t/4+j*p+k*p/2,q))w=240
https://www.dwitter.net/d/15182
c.width|=0;with(x)for(globalCompositeOperation="difference",k=81;beginPath(p=1.5708),k--;fillStyle=`hsl(${t*9} 99%60%`,fill(),t=-t)for(j=4;j--;arc((k%9)*w,(k/9|0)*w-60,w,q=t/4+j*p+k*p/2,q))w=240