diff --git a/src/base.h b/src/base.h
index 143384e..653ebc3 100644
--- a/src/base.h
+++ b/src/base.h
@@ -39,8 +39,8 @@ typedef double f64;
 #define NUM_PROGRAMS_POW_2   8
 #define NUM_PROGRAMS         (1 << NUM_PROGRAMS_POW_2)
 
-#define MUTATION_CHANCE 0
-#define MUTATION_OFFSET 2
+#define MUTATION_CHANCE 10000
+#define MUTATION_OFFSET 3
 
 #endif
 
diff --git a/src/simulation.c b/src/simulation.c
index bae71cc..731ab00 100644
--- a/src/simulation.c
+++ b/src/simulation.c
@@ -29,7 +29,7 @@ void simulation_iterate(simulation_t *sim)
 #if MUTATION_CHANCE
   for (u64 i = 0; i < SIMULATION_SIZE; ++i)
   {
-    if ((rand() % MUTATION_CHANCE) == 0)
+    if ((rand() % MUTATION_CHANCE) == (MUTATION_CHANCE - 1))
     {
       sim->memory[i] += (rand() % MUTATION_OFFSET) - (MUTATION_OFFSET / 2);
     }