String puzzles

Some puzzles from the thesis of Davide Maglia.

Puzzle 1. Here is a puzzle made of blocks of wood and strings:

The problem is to disentangle it (without cutting the strings!) so that it becomes:

Then re-entangle it to get the original configuration!

Puzzle 2. Do the same with

Maybe they were too easy. Try your luck with the next puzzles!

Puzzles 3 and 4 See if you can untangle the first two to obtain in each case the third: