Correct Example [#1984]

of: 101 Contour (ISOM 2017-2)
from: Petrov nad Desnou, Czechia

Long re-entrant example (probably formed as a result of historical mining).

Long re-entrant probably formed as a result of historical mining near Petrov nad Desnou, Czechia. Photo by: Luděk Krtička (CC BY-SA 4.0)