diff --git a/src/calc.c b/src/calc.c
index 377ec72..d4d55d9 100644
--- a/src/calc.c
+++ b/src/calc.c
@@ -1,11 +1,17 @@
+#include "stdint.h"
+
 void main() {
-    int wait = 0xfffffff;
+    uint32_t wait = 0xfffffff;
 
-    unsigned int *vidmem = *(unsigned int**)(0x5000 + 40);
+    uint32_t* vidmem = *(uint32_t**)(0x5000 + 40);
 
-    vidmem[8000] = 0x00ffffff;
+    for (uint32_t x = 200; x < 400; x++) {
+        for (uint32_t y = 200; y < 400; y++) {
+            vidmem[y * 1920 + x] = 0x00ffffff;
+        }
+    }
 
-    while (wait != 0) wait--;
+    while (wait--);
 
     return;
 }