Are you talking about something like this:

                     |
                     |
                     |\    
                     | \
                     |  \
                     |   \
                     |    \
                     |     \
             <=      |      \
===================================
                     |
===================================
             =>      |       \
                     |        |
                     |        |
                      \      /
                       \____/

?