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

1. Change the shape of the object to resemble a square block. This means the object should have a square base and four equal sides.
2. Add a circular cutout in one corner of the object. 
3. The circular cutout should look like one quadrant of a circle was taken out. This means the cutout should be a quarter of a full circle. 

Please ensure that the object remains extruded in one dimension as this aspect of the design is correct.