PROC main (CHAN INT in?, out!)     PROCsquare (CHANINTc?, d!)
  CHANINTa, b:             INT x,y:
  PAR                 SEQ
  square (in?,a!)          c?x
  square (a?,b!)            y = x * x
  square (b?,out!)          d!y
:                   :
Code Example 1: An program.