Heated flare loops of six hard microflares with SDO/AIA 131 Å images. Overlaid on the AIA 131 Å images are reference loops: a solid orange semi-circle perpendicular to the solar surface, with a radius defined as half the distance between the UV ribbons (AIA 1600 Å, green contours), and a dashed orange semi-ellipse, where its semi-minor axis is half of the semi-major one. The latter is considered a reference for flat loops.