First the original - a pencil scetch of Pohjoisranta, Helsinki, Finland, 6th May 2004.
Then the first modification: some shades of old drawings...
Second...blue sky...
Third: some more tones...
PICASA is very practical tool, indeed.
In the middle of business or free-time trip - just take some time to see views. No hurry, only some hours with yourself and the views around you. Pencils, ink, charcoal, some colours...Maybe some photos to carry home for long and dark winter days.