Triangle Gears

https://www.dwitter.net/d/15159

Javascript...

for(c.width|=0,k=49;x.beginPath(p=2.0944),k--;x.fill(),t=-t)for(j=6;j--;x.arc(600+(k%7)*w,180+(K=k/7|0)*w,80,q=t+j*p+k*p/2+(k+K&1),q))w=120