Form element, arrangement of the form element and method for forming at least one part of a formwork for a concrete part with the form element

A form element for forming at least part of a formwork for a concrete part, comprising:

• a plurality of flexible layers which are arranged one above the other, wherein the plurality of flexible layers have a first configuration and a second configuration;
• and
• an airtight envelope that surrounds the plurality of flexible layers;
• wherein, in the first configuration, the form element is flexibly and reversibly and three-dimensionally deformed by movement of at least one layer of the plurality of flexible layers relative to an adjacent layer of the plurality of flexible layers;
• wherein, in the second configuration, the form element is stiffened and solidified in a deformed position by reversible connection of at least one layer of the plurality of flexible layers to an adjacent layer of the plurality of flexible layers which solidifies the form element, which is provided by at least one pump configured to extract air from the airtight envelope.