OK here is a Zone 1 puzzle for you which is like a dot-to-dot puzzle.
Follow this route with a thick marker pen and then rotate the route through 90 degrees anti-clockwise. It may help to photocopy your route onto a plain white piece of paper and look at the image upto the light.
PM me with your answer on what you think the image looks like

OK here is the route:
Start: Regents Park (once its opened!)
Charing Cross
Leicester Sq.
Kings Cross
Moorgate (by H&C/Met/Cir)
Euston
Tottenham Court Road
Liverpool Street
Aldgate
run Aldgate East
Embankment
Elephant & Castle
London Bridge
Waterloo
Vauxhall (by nat rail)
Victoria
Sloane Sq.
Westminster
Green Park
Earls Court
Bayswater
run to Queensway
Bond Street
Baker Street
Paddington
Finish: Euston Sq.
Can you see what it is yet
