Answer
$A_{3D}=(A_{1D}{\oplus I}\oplus I)+(I\oplus A_{1D}{\oplus I})+(I {\oplus I}\oplus A_{1D})$$
Work Step by Step
As we know that:
The first dimension : $(A_{1D}{\oplus I}\oplus I)$
The seconddimension : $(I\oplus A_{1D}{\oplus I})$
The third dimension : $(I {\oplus I}\oplus A_{1D})$
Just sum all directions, we get
$A_{3D}=(A_{1D}{\oplus I}\oplus I)+(I\oplus A_{1D}{\oplus I})+(I {\oplus I}\oplus A_{1D})$
