Chinese postman problem
Arrow keys - move
Enter - accept
P - pause
The only level in Easy Eulerian is the graph from question 2b) of assignment 2 with some edges removed.
The first level of Hard Hamiltonian is the cube (but not all edges have the same length). The second level of Hard Hamiltonian is the dodecahedron (and all edge have the same length).
Given a set of edges to double, there are different ways to execute the final Eulerian cycle (with different scores). This was unintended but the score different is minimal.