4 puzzles + 1 mathematical puzzle hidden in one of the puzzles.
Secret box: Open the box.
Secret padlock: Open the padlock.
Trapped nails: Separate the nails and connect them as before.
3D wooden cube: Take apart and put together.
Mathematical puzzle: Obtain the same sum in each column.
Secret box: 4/6
Secret padlock: 3/6
Trapped nails: 4/6
3D wooden cube: 3/6
Mathematical puzzle: 3/6
Secret box: 7.5 x 9.4 x 4.3 cm
Secret padlock: 6 x 4.5 x 1.5 cm
Trapped nails: 5 x 5 x 2 cm
3D wooden cube: 5 x 5 x 5 cm