Plane net of a tetrahedron
A regular tetrahedron is a polyhedron with four equilateral triangular faces, four vertices and six edges. It is a Platonic solid.
It was Durer the first to publish plane nets of polyhedra. In his book 'Underweysung der Messung' ('Four Books of Measurement', published in 1525) the author draw plane developments of several Platonic and Archimedean solids, for example, this regular tetrahedron:
"[Durer] He introduces a technique of conveying information about three-dimensional objects on a flat surface via paper-folding which in modern times is called a net. The method involves developing the surface of a polyhedron onto a plane sheet of paper so that the resulting figure can be cut out as a single connected piece then folded up to form a three-dimensional model of the original polyhedron". (Cromwell, p.127)
Playing with the application you can see how a tetrahedron develops into a plane net. This is a very typical plane net of a tetrahedron but it is different from the plane net that Durer drew:
In the next application we can see the plane development of a tetrahedron as Durer did:
Erwin Panofsky - The Life and Art of Albrecht Dürer - Princeton University Press
Dan Pedoe - Geometry and the Liberal Arts - St. Martin's Press (p. 76)
Hugo Steinhaus - Mathematical Snapshots - Oxford University Press - Third Edition (p. 197)
Magnus Wenninger - 'Polyhedron Models', Cambridge University Press.
Peter R. Cromwell - 'Polyhedra', Cambridge University Press, 1999.
H.Martin Cundy and A.P. Rollet, 'Mathematical Models', Oxford University Press, Second Edition, 1961 (p. 87).
W.W. Rouse Ball and H.S.M. Coxeter - 'Matematical Recreations & Essays', The MacMillan Company, 1947.