square plate 3d model

A square of 7.74 mm by 7.74 mm and with a thickness of 3.12 mm. The thin sides need to have a horizontal indentation of 0.72 mm deep and 0.72 mm wide along the entire length of 7.74 mm. Perpendicular to that indentation, each side needs to have another indentation of 0.72 mm deep and 0.72 mm wide over the entire thickness of 3.12 mm, and which crosses the existing indentation in the middle.