Dr Murks and 5 new cars

For a weekend a family visited the flat. "Why your room is so messy?" asked Sanna (5 years). "Because I am messy and need all my papers close at hand," Dr Murks had to answer. "Why do not you have any small cars models to play to?" asked Siim (3 years). "Hmmmm," Dr Murks had nothing to answer. But Siim took a piece of firewood by the oven and draw wheels and lights and windshield on it - a car was there. Soon Dr Murks had 5 brand-new cars. Hmmmmmm, not bad.