<pre>
The three columns represent the left bank, the boat, and the right bank
respectively.  The < or > indicates the direction of motion of the
boat.

The fox, the duck, and the corn
 fdc     .       .
 fc      d>      .
 fc      <       d
 f       c>      d
 f       <d      c
 d       f>      c
 d       <       fc
 .       d>      fc
 .       .       fdc

Three missionaries and three cannibals
 mmmccc  .       .
 mmcc    mc>     .
 mcmc    <m      c
 mmm     cc>     c
 mmm     <c      cc
 mc      mm>     cc
 mc      <mc     mc
 cc      mm>     mc
 cc      <c      mmm
 c       cc>     mmm
 c       <c      mmmc
 .       cc>     mmmc
 .       .       mmmccc

Three humans, one big monkey, two small monkeys (Dudeney, Puzzle-Mine, #164)
 HMhhmm .       .
 Hhhm    Mm>     .
 Hhhm    <M      m
 Hhh     Mm>     m
 Hhh     <M      mm
 hM      Hh>     mm
 hM      <Hm     hm
 hm      HM>     hm
 hm      <Hm     hM
 mm      Hh>     hM
 mm      <M      Hhh
 m       Mm>     Hhh
 m       <M      Hhhm
 .       Mm>     Hhhm
 .       .       HMhhmm

Three jealous husbands and their wives
 ABCabc  .       .
 ACac    Bb>     .
 ACac    <B      b
 ABC     ac>     b
 ABC     <a      bc
 Aa      BC>     bc
 Aa      <Bb     Cc
 ab      AB>     Cc
 ab      <c      ABC
 b       ac>     ABC
 b       <B      ACac
 .       Bb>     ACac
 .       .       ABCabc
</pre>
