diff --git a/springstiff.m b/springstiff.m
new file mode 100644
index 0000000000000000000000000000000000000000..16a6754a7e37fb90db569a38f65dfb605b674b64
--- /dev/null
+++ b/springstiff.m
@@ -0,0 +1,7 @@
+function [k] = springstiff(stiff)
+%spring stiffness
+
+k=[stiff -stiff;-stiff stiff];
+
+end
+