/  1320 Plain Bob Doubles

5 bells
11 extents

PlainBob = &5.1.5.1.5

p = PlainBob, +25, "  @"
b = PlainBob, +45, "- @"

obs4 = 3(b, p, p, p)
obs2 = 3(p, b, p, p)
obs3 = 3(p, p, b, p)
obs5 = 3(p, p, p, b)
prove 2 obs4, 2 obs2, 2 obs3, 2 obs5, 3 obs4