Help with 3-D Sudoku?

Question

Place one digit (1-9) into each unit cube of a 3x3x3 cube such that each square layer of nine unit cubes contains all nine digits. There are nine such square layers, three in each of the three directions.

Answer 1

1 2 3
4 5 6
7 8 9

9 6 4
8 1 7
2 3 5

5 7 8
3 9 2
6 4 1