f) said second flat side having {HEAD ~ a second hole} complementary to said {TAIL ~ first flat side hole} with a catch; and 
f ) said second flat side having { HEAD ~ a second hole } complementary to said { TAIL ~ first flat side hole } with a catch ; and
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH