89 ISSUE/PROBLEM (society issue, issue that is seen relevant from pupils’ perspective, issue linked to some nature phenomenon or phenomenon from pupils’ everyday life) How much do you have to see to recognize a face? INVESTIGATIONAL STAGE DESCRIPTION OF THE ACTIVITY Topology is a component of mathematics that studies spatial forms such as continuity and the properties of objects that do not change when, for example, the object is twisted or stretched without tearing or glueing. The term is also used in other fields, such as biology and music. TASKS Watch a five-minute OTA video in which topology expert Kirsi Peltonen and art expert Anu Utriainen share their thoughts of the self-portrait of Finnish artist Helene Schjerfbeck from 1915. https://vimeo.com/693504226/c4c746560e Print a self-portrait or facial image from the web and reveal only a small part of it. You can also cut a piece of the print and guess with the others which part of the face it belongs to. Is it possible to conclude to which part of face it belongs into? The smaller the piece, the harder it is to guess. Find a printable face either on the website of the National Gallery of your home country or on the website of the Louvre Museum in Paris. https://collections.louvre.fr/en/ark:/53355/cl010062370 GOAL OF TASKS Understand the basic concepts of topology in the field of mathematics and that a work of fine art is the sum of its parts.