(bind-func fluid_fsc
  (let ((step 0:i64))
    (lambda ()
      (set! SIM_ACTIVE #t)
      (spawn (lambda ()
               (while (= #t SIM_ACTIVE)
                 (thread_sleep 0 100000)
                 (if (< step StepNum)
                     (begin (set! step StepNum)
                            (fluid_step_cube (get_fluid_cube))))
                 void)))
      void)))