Eagle to me feels like adult puzzles. I really enjoyed getting to know it while doing these exercises and felt like I was solving a modern and functional puzzle.
The first and second schematics were simple to complete. However, the third one took me a bit longer. At first I thought that it wasn't possible to finish without adding an underpass, but I didn't want to add to because it would mean that this schematic is only valid for double-sided copper plates, and they are more expensive and not always as available.
I got it working after shuffling around components and a lot of trial and error.
Above: Schematic 1
Left: layout before traces.
Right: completed layout with traces.
No real difference int the component placements between the two images above.
Left: layout before traces
Right: completed layout after traces
I had to move the components around a lot to find the positions on where they made it possible to connect all the nodes with no overlap.