Based on the answers provided, the following corrections need to be made to the 3D object:

1. Modify the object to resemble an upside-down table. This can be achieved by creating a flat surface supported by legs, which is typical of a table structure. 

2. Ensure that the upright columns of the object are wider than the horizontal section. This can be done by increasing the width of the columns while maintaining the width of the horizontal section. 

Please note that while making these changes, the "U" shape of the object and its extrusion in one dimension should be preserved.