By 1954, Christiansen's son, Godtfred, had become the junior managing director of the Lego Group. It was his conversation with an overseas buyer that led to the idea of a toy system. Godtfred saw the immense potential in Lego bricks to become a system for creative play, but the bricks still had some problems from a technical standpoint: their locking ability was limited and they were not versatile. In 1958, the modern brick design was developed; it took five years to find the right material for it, ABS (acrylonitrile butadiene styrene) polymer. The modern Lego brick design was patented on 28 January 1958.
Colour-wise, it is mainly yellow, with only a dash of green and red, and a little more white, there to break it up. The worker has space to stand and drive the vehicle, and has a walkie talkie attached on the side of the car. Around the other side is a coiled-up, what I assume is a, fuel pump. It looks pretty good when coiled up on the side of the car. Stickers come into use again here, this time for the number plates.