An umbrella structure includes a cover, a shaft, {HEAD ~ a notch}, a runner, {TAIL ~ main ribs} and stretchers 
An umbrella structure includes a cover , a shaft , { HEAD ~ a notch } , a runner , { TAIL ~ main ribs } and stretchers
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH