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

1. Change the second shape to a right triangular prism. Currently, it appears to be a smaller cube or another polyhedron with equal-length edges. It needs to be modified to have a rectangular side and two triangular faces to correctly represent a right triangular prism.

2. Adjust the size of the second shape to be exactly 1/4th the size of the first shape. Currently, it's unclear if the second shape is exactly 1/4th the size of the first shape. This needs to be clearly depicted in the 3D model.