# Test case (all resistors one-ohm):
#
#          +---/\/\/---a---------------/\/\/---------------+
#          |           |                                   |
#  1V--e---+           +---/\/\/---d---/\/\/---b---/\/\/---+---gnd--0V
#          |                                               |
#          +---------/\/\/---------c---------/\/\/---------+
#
# The equivalent resistance is easy to work out in this case.  The
#  gnd-c-e path has resistance 2; the gnd-b-d-a path has resistance 3,
#  so the gnd-a effective resistance is 1/((1/1)+(1/3))=1/(4/3)=3/4,
#  giving the gnd-e path through a a resistance of 7/4.  Then the total
#  resistance is 1/((4/7)+(1/2))=1/((8/14)+(7/14))=1/(15/14)=14/15.
#
# Total current is thus 15/14.  gnd-c and c-e carry 1/2 each, with a-e
#  carrying the other 8/14=4/7; of this 4/7, gnd-a carries three times
#  what gnd-b-d-a carries, so the currents are 3/7 for gnd-a and 1/7
#  for gnd-b, b-d, and d-a.

V gnd 0
R gnd a 1
R gnd b 1
R gnd c 1
R a d 1
R b d 1
R a e 1
R c e 1
V e 1