Based on the answers provided, here are the corrections needed for the 3D object:

1. Change the shape of the main body of the object from a rectangle to a square while maintaining the grooves and the attached smaller rectangles. 

2. Ensure that the smaller rectangles have around 1/5th of the width of the square but maintain the same length. This might need some trial and error to get the proportions right since the exact measurements are not provided.