(use srfi-18)

#>
static double clock_d()
{
	return clock() / (double)CLOCKS_PER_SEC;
}
static void draw()
{
	double t = clock_d();
	int i;
	while ((clock_d() - t) < .033)
		i++;
}
<#
(define draw (foreign-lambda void "draw"))

(use srfi-18)

(define (a)
	(draw)
	(print "A:" (current-seconds))
	(a))

(define (b)
	(print "B:" (current-seconds))
	(b))

(thread-start! (make-thread b "B"))

(a)