Brainteasing Puzzlers

A Eureka puzzler. Remove the Und then put it back again.

Difficulty level 1

A Eureka Mini string and wood puzzle. Separate the two rings and then put them back. 7.5 x 14 x 1cm

Difficulty level 2

A Eureka puzzler. Remove the rope and then put it back.

Difficulty level 2

A Eureka Mini string and wood puzzle. Make the two hemi-spheres change direction and face each other. 7 x 14 x 3.5cm

Difficulty level 2

Can you take this apart and reassemble it? Attractively boxed and made by Hanayama in Japan. Difficulty level 6. 1 is easiest and 6 is the hardest. No solution given.