Suddenly you are stopped. This was the way to your destination and you find you cannot go on. You could try to destroy the obstacle. You could try to go around and perhaps get stuck. Or, you could turn around and find a new way. That is what I will do. Nikon F4 with the Voigtlander 40mm F2 Lens. Fomopan 100 developed in Rodinal 1:50 for 9 minutes.