[ODE]How can ode implement a pulley system?

[revv00 at mails.tsinghua.edu.cn]

Hi, all:
  I am searching a method to accomplish my course project and find ODE a rather
good engine, Here is my problem:
  It seems hard to implement a dynamic process of a pulley system, take the
following case for example,('@' for the wheel, two 'O' for objects which are
supposed to contacted with the Triangle,'\'connected with the 'O' is for the ideal
ropes.)
  Thank you so much, please take this case in to consideration.

          |@\
          ||\\
          || \\
          O|  \O
    _______|___\________slippy ground