Gustav Lilienthal was working on children's toys when he noticed something about wooden blocks. They are light, and their faces are smooth, so a tower built from them comes apart at a touch. Real buildings do not behave that way. Real buildings stay up because stone is heavy and stone is rough.
So he set out to make blocks that were actually stone-like. With his brother Otto, an engineer, he worked out a mixture of quartz sand, powdered chalk and pigment, bound with linseed oil varnish and pressed into moulds. The colours were chosen to match real building materials: red for brick, cream for limestone, blue-grey for slate.
They were designed as a counterpart to Friedrich Fröbel's wooden kindergarten blocks, which had been shaping how German children were taught to build for decades.
Sold for a Thousand Marks
The engineering was sound. The selling was not.
The brothers could not make the blocks pay. They fell into debt and, in 1880, sold the formula and the machinery to Friedrich Adolf Richter, a businessman in Rudolstadt in Thuringia, for a thousand marks.
Richter understood what he had bought. He built a dedicated factory for the stones in 1882, and set up an art institute, a Kunst Anstalt, staffed with artists, illustrators and architects, purely to draw up the building plans that came with each set. He named them Richter's Anchor Stone Building Sets in 1894. Over the following decades more than six hundred different sets appeared, and more than a thousand stone shapes.
Gustav Lilienthal emigrated to Australia the same year they sold, and worked there as an architect. Otto stayed with the problem that would make him famous, and became the first person in the world to make repeated successful glider flights.
Who Built With Them
The list of children who grew up with a set is strange for a toy.
Albert Einstein had one, and some of his stones survive. So did the physicists Max Born and Robert Oppenheimer. So did Ivan Sutherland, who went on to invent much of computer graphics. And so did Walter Gropius, who founded the Bauhaus, which is perhaps the least surprising name on the list.
Sets have since been exhibited at the Louvre and the Deutsches Museum in Munich.
Nothing Holds Them Together
This is the part worth understanding before you open a box.
There are no studs. No clips. No interlocking of any kind. The stones stay where you put them because they are heavy and because their surfaces catch on one another, which is exactly how a real wall stands. Build badly and it falls, for the same reasons a badly built wall falls.
The stones are also cut to a fixed calibre, and have been since the beginning. A set bought this year will fit with stones cut a century ago.
Stopped, and Started Again
Production ended in 1963, under the East German government, and the machinery was dispersed. For decades the only Anchor stones in the world were the ones already in cupboards.
They were revived in the 1990s, and since 2017 they have been made again in Rudolstadt, in the same town, by Ankerstein GmbH, which is owned by a local workers' welfare association and run as an inclusive business.
The formula is unchanged. Quartz sand, chalk and linseed oil, pressed into moulds, heavy enough to stay where they are put.