Object: Attack all positions.

You are given various 3-dimensional boards (variant 1 uses a 2x5x5 board), and a number of identical chess pieces to drop onto the board.
In each move you drop a yellow token on any empty square of the board.
Attacked positions are marked by green tokens.

The goal is to have all positions attacked while using as few dropped pieces as possible.
The shortest known number of moves for total coverage is indicated next to the counter.

Beginners:
Attack all positions.
The system issues a win-message once all positions are covered.
Experts:
Attack all positions with the minimum number of chess pieces placed.

Variants:
The variants play on the 2x5x5, 4x4x4, 4x5x5, and 5x5x5 boards.
They use the chess pieces Knight, Rook, Bishop, Queen and King.

Solutions with the smallest known number of moves are attached.