[ZenGum]

These were taken by Justin Quinnell, using a pinhole camera made from a soda can and duct tape, with a SIX MONTH exposure. Thus they show the track made by the sun from solstice to equinox. There are more pictures, and detailed instructions at his website and plenty from other people all around the world here.
The streaks are the tracks made by the sun, and the gaps indicate cloudy weather.