Practices of yesterday and today
Redoubling ingenuity, the artisans of mosaics adorning the monuments of the Roman Empire, the builders of the Middle Ages or the designers of sangaku, these astonishing Japanese tablets, have widely used the two favorite instruments. But this is also the case (virtually) of today's dynamic geometry software, which always meet the same needs: copying lengths and connecting points. As for the very recent mathematical theory of origamis, it relies on... the absence of a ruler and compass, but the properties of lines and circles are still just as present!
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Circles in ancient Roman mosaics | Tangente
Besides their undeniable aesthetic appeal, mosaics and other archaeological remains from our past often hold wonderful mathematical surprises. These geometric examples from Gallo-Roman sites offer ample proof.
Origami and folds for geometric constructions
Greek geometers regarded only straightedge-and-compass constructions as acceptable. Some problems that defeated their ingenuity—for reasons that would not be understood until the advent of algebra—can nevertheless be solved using origami.
Dynamic geometry in action with GeoGebra | Tangente
Developed in 2002 by an Austrian student, GeoGebra is an educational tool with an unusual history. Designed for mathematics teachers worldwide, it is especially popular among secondary-school teachers in France. Tangente spoke with the software's creator, Markus Hohenwarter.
Bernard Cornet's geometric art and Voronoi | Tangente
In art, mathematical tools can help artists develop and create their work. The Nantes painter Bernard Cornet (born in 1952) has brought Voronoi diagrams and Delaunay triangulation into his artistic practice.
The builders' geometric constructions
Several centuries before the Renaissance, whether building a church or a fortress, builders needed only a compass and an unmarked straightedge to draw arcs, pointed arches, basket-handle arches and rose windows. Let us explore the basic geometry behind their methods.
Drawing a circle: a geometric challenge | Tangente
During the last lockdown, travel in metropolitan France was restricted to within 10 km of the address where people were staying during that period. Now there is a rule guaranteed to pique the curiosity of mathematics enthusiasts!
Jacques Dominioni
The work shown on the cover of this special issue of Tangente is a painting by Jacques Dominioni.
Computer geometry: Cabri and GeoGebra | Tangente
Although computer drawing had been possible since the 1970s, so-called "dynamic geometry" software did not become widespread until the 1980s.