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

1. The two smaller rectangles need to be repositioned so that they are connected to the center of the longer edges of the main rectangle. Currently, they are positioned towards one end of the main rectangle.

2. The circular hole needs to be relocated to the center of the object. Currently, it is offset towards one end of the object.

3. To make the object clearly resemble a puzzle piece, consider adding more distinctive features of a puzzle piece, such as interlocking tabs and blanks, while maintaining the overall rectangular shape and other features.