diff --git a/fmmd_concept/System_safety_2011/state_exp.c b/fmmd_concept/System_safety_2011/state_exp.c
new file mode 100644
index 0000000..098e953
--- /dev/null
+++ b/fmmd_concept/System_safety_2011/state_exp.c
@@ -0,0 +1,54 @@
+
+#include <stdio.h>
+
+
+int rcalc ( int n, int fgn, int cfn , int level)
+{
+	int retval = 0,i;
+
+
+	printf("level: %d     n %d   fgn %d   cfn %d \n", level, n,fgn, cfn);
+
+
+	level ++;
+
+	if ( n/fgn < fgn ) 
+		retval =  n%fgn * cfn;
+	else 
+		retval += rcalc(n/fgn, fgn, cfn, level);
+
+	retval += n + (fgn-1) * fgn * cfn;
+
+	// now calculate how many to do on this level
+	//
+	return retval;
+}
+
+
+
+
+main () {
+
+        int r, n, fgn, cfn;
+
+	printf(" \n State explosion FMMD approximation \n");
+	printf(" Enter number of base components: ");
+        fflush(stdout);	
+	scanf("%d",&n);
+
+	printf(" Enter number of components in functional group: ");
+        fflush(stdout);	
+	scanf("%d",&fgn);
+
+	printf(" Enter number of failure modes for each component:");
+        fflush(stdout);	
+	scanf("%d",&cfn);
+
+	r = rcalc ( n, fgn, cfn, 0 );
+	printf(" for single failures FMMD=%d components cross prod failure modes %d\n",r,n*(n-1)*cfn);
+
+}
+
+
+
+