wherein said front end portions and front gap portions are in the front direction of {HEAD ~ the movement} of {TAIL ~ the shoe} while said rear end portions and rear gap portions are rearward respectively to said front face portions and said front gap portions 
wherein said front end portions and front gap portions are in the front direction of { HEAD ~ the movement } of { TAIL ~ the shoe } while said rear end portions and rear gap portions are rearward respectively to said front face portions and said front gap portions
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH