The second blackboard problem in the 1997 film Good Will Hunting asks for all the series-reduced trees (referred to
by the alternate term "homeomorphically irreducible trees" in the film)
on 10 nodes. Here, "series-reduced" means there are no vertices of degree
2 so that a topologically equivalent structure can be obtained by merging two incident
edges at a vertex (i.e., no node merely allows a single edge to "pass through").
There are exactly 10 such trees, illustrated above (though only eight of them are
drawn by the character Will in the film).
