IMO 1984 LL FRG23

A 2 imes 2 imes 12 box fixed in space is to be filled with twenty-four

IMO 1984 LL FRG23

Origin: FRG

Problem

A 2 \times 2 \times 12 box fixed in space is to be filled with twenty-four 1 \times 1 \times 2 bricks. In how many ways can this be done?