diff --git a/xormod.c b/xormod.c
index 13d3eab..51d6c79 100644
--- a/xormod.c
+++ b/xormod.c
@@ -51,11 +51,12 @@ static Picture *Picture_new(SDL_Renderer *rend,
 typedef uint32_t uint32_8 __attribute__ ((vector_size (8 * sizeof(uint32_t))));
 
 static void Picture_render(Picture *p, SDL_Renderer *rend) {
+    int w = p->w, h = p->h;
     uint32_8 c = p->color - (uint32_8){};
-    uint32_8 y = 0 - (uint32_8){};
-    for (int j = p->y1, r = 0; j < p->y2; j++, y+=1) {
-        uint32_8 x = {0, 1, 2, 3, 4, 5, 6, 7};
-        for (int i = p->x1; i < p->x2; i+=8, r+=8, x+=8) {
+    uint32_8 y = p->y1 - (uint32_8){};
+    for (int j = 0, r = 0; j < h; j++, y += 1) {
+        uint32_8 x = p->x1 + (uint32_8){0, 1, 2, 3, 4, 5, 6, 7};
+        for (int i = 0; i < w; i += 8,r += 8, x += 8) {
             uint32_8 z = (x ^ y) % 9;
             uint32_8 f = (z==0) & c;
             memcpy(&p->pixels[r], (uint32_t*)&f, sizeof(f));