Swedish lesson

Notice about the windows getting painted during the summer. Two Swedish things about it:
1. Swedes use week numbers. "I'm going on holiday week 28-29" they say and expect you to know exactly when that is...
2. Swedes like writing "Obs!" as in "Observera!", meaning "Note" (lit. "observe"). (There shouldn't be any dots between the letters though, but hey who am I to fly back into the country and start correcting the locals...?)