The block back legs may extend in {TAIL ~ a plane} parallel to {HEAD ~ the block front surface} or extend forwardly toward the blocks front surface 
The block back legs may extend in { TAIL ~ a plane } parallel to { HEAD ~ the block front surface } or extend forwardly toward the blocks front surface
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH