diff --git a/quad10/fenomens/lab/p3/writeconfigseed.f90 b/quad10/fenomens/lab/p3/writeconfigseed.f90
new file mode 100644
index 0000000..f7c8570
--- /dev/null
+++ b/quad10/fenomens/lab/p3/writeconfigseed.f90
@@ -0,0 +1,16 @@
+subroutine WRITECONFIGSEED(S, L, SEED)
+  implicit none
+  integer*4, intent(in) :: L
+  integer*4, intent(in) :: SEED
+  integer*2, intent(out) :: S(1:L,1:L)
+  integer*4 :: i, j
+  real*8 :: genrand_real2
+
+  call init_genrand(SEED)
+
+  do i = 1, L
+    do j = 1, L
+      S(i, j) = merge(1, -1, genrand_real2() < .5d0)
+    enddo
+  enddo
+end subroutine WRITECONFIGSEED