%
% specification for simple graphics interaction
%

specification((
+((
  (stop-> keep(red)),
  (start->
      (length(4),keep(green)
      )
      & keep(red)),
  next(halt((start;stop;quit)))
  )),
[]((red,not(green);not(red),green)),
[]((green->move)),
[]((red->not(move))),
halt(quit)
)).

st_variables([stop,start,quit],[red,green,move]).