diff --git a/quad10/fenomens/lab/p4/writeconfig.f90 b/quad10/fenomens/lab/p4/writeconfig.f90
new file mode 100644
index 0000000..b356d17
--- /dev/null
+++ b/quad10/fenomens/lab/p4/writeconfig.f90
@@ -0,0 +1,20 @@
+subroutine WRITECONFIG(S, L)
+  implicit none
+  integer*4, intent(in) :: L
+  integer*2, intent(out) :: S(1:64,1:64)
+  integer*4 :: SEED, i, j
+  real*8 :: genrand_real2
+
+  SEED = 23456
+  call init_genrand(SEED)
+
+  do i = 1, L
+    do j = 1, L
+      if (genrand_real2() < .5d0) then
+        S(i, j) = 1
+      else
+        S(i, j) = -1
+      endif
+    enddo
+  enddo
+end subroutine WRITECONFIG