Perpetuum mobile

Marek's rickshaw once broke on Piccadilly. He could do absolutely nothing about it. One of the chains snapped and he had neither a spare one nor a chain breaker tool. There was no remedy. He had to push it back to the base. Somewhere on Piccadily a stroke of good luck sweetened a bit his misfortune. He met a friend of his who seeing him in trouble offered a helping hand. "Get on the saddle and steer. I'll give you a push!" Never minding his smart clothes, that friend of Marek pushed the trike energetically. Thus, pretty soon, they reached Piccadilly Circus. A police officer looked at the show, including a smartly dressed guy, a tricycle and an idle rickshaw rider and knew straight away that the thing in front of him was not one of a perpetual motion. Adressing Marek's friend he asked: "Excuse me! How much did you pay for this lift, sir?"