Altarpiece of the Saints John Altarpiece of the Saints John The Altarpiece of the Saints John is a painting by Bernat Martorell conserved at the National Art Museum of Catalonia. The "Altarpiece of the Saints John" from Vinaixa was commissioned in 1432 from the Tarragona painter Ramon de Mur, but in the end it was painted by Martorell. The MNAC keeps most of the panels from this altarpiece. The main panel is kept at the Museu Diocesà de Tarragona, a side compartment is kept at the Musée Rolin d'Autun (France), and the whereabouts of another compartment is unknown. The two Saints John feature in the
Hinged dissection Hinged dissection A hinged dissection, also known as a swing-hinged dissection or Dudeney dissection, is a kind of geometric dissection in which all of the pieces are connected into a chain by "hinged" points, such that the rearrangement from one figure to another can be carried out by swinging the chain continuously, without severing any of the connections. Typically, it is assumed that the pieces are allowed to overlap in the folding and unfolding process; this is sometimes called the "wobbly-hinged" model of hinged dissection. The concept of hinged dissections was popularised by the author of mathematical puzzles, Henry Dudeney.