Perugia Altarpiece Perugia Altarpiece The Perugia Altarpiece (Italian: "Pala di Perugia") is a painting by the Italian early Renaissance painter Fra Angelico, housed in the Galleria Nazionale dell'Umbria of Perugia, Italy. The painting was executed for the St. Nicholas Chapel in the Basilica of San Domenico, Perugia. In the early 19th century, it was split and partially dispersed, and some of the predella panels were acquired by the Pinacoteca Vaticana. In Perugia were executed copies of these panels, enclosed into a neo-Gothic frame. The polyptych also included some small depictions of saints, on the side piers, and two tondoes with the "Annunciation
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.