What does "leave clear on its left" mean in UK regulations relating to collision avoidance on non-runway landings? This doesn't seem to be plain English, could someone explain this with a simple example for me please? I'm not sure what 'Leave clear on it's left' means, and it's not clear whether the subject of the sentence is 'A flying machine [etc.]' or 'An aircraft that has landed' (i.e. who's left are we talking about) 


  Landing and take-off 
  
  (2) If take-offs and landings are not confined to a runway—
  
  (a) when landing, a flying machine or glider must leave clear on its
  left any aircraft which has landed, is already landing or is about to
  take off; 
  
  (b) a flying machine or glider which is about to turn must
  turn to the left if the commander of the aircraft is satisfied that
  such action will not interfere with other traffic movements; and
  
  (c) a
  flying machine which is about to take off must take up position and
  manoeuvre in such a way as to leave clear on its left any aircraft
  which has already taken off or is about to take off.


(CAA:"The Rules of the Air Regulations 2015 ")

I've tried searching for the term online but only seem to be able to find excerpts from the legislation.
Seems understandable to me.
It may be more clear with commas...
"(a) when landing, a flying machine or glider must leave clear, on its left, any aircraft which has landed, is already landing or is about to take off;"

Basically leave enough room between you and any aircraft which may be on your left as you pass them.

The grammar may be a little dated but still perfectly accurate.