Anchor

An anchor comprising:

• a first flange;
• a second flange;
• a third flange, the second flange being disposed between the first flange and the third flange, a surface of the first flange facing the second flange defining a plane, a contour of the first flange projected onto the plane extending beyond a contour of the second flange projected onto the plane;
• a base connecting part, the base connecting part including the third flange and the second flange;
• and
• an accessory connecting part operatively connected to the base connecting part, the accessory connecting part including the first flange,
• the third flange being movable relative to at least one of the first and second flanges between a first position and a second position,
• when in the first position, a contour of the third flange projected onto the plane is contained within the contour of the second flange projected onto the plane, and
• when in the second position, the contour of the third flange projected onto the plane extends beyond the contour of the second flange projected onto the plane.