diff --git a/part12-wgt/wgt.c b/part12-wgt/wgt.c
index 4a648b6..826e50a 100644
--- a/part12-wgt/wgt.c
+++ b/part12-wgt/wgt.c
@@ -19,7 +19,6 @@ void *memset(void *dest, unsigned int val, unsigned len)
     return dest;
 }
 
-
 void *memcpy(void *dest, const void *src, unsigned len)
 {
     unsigned int *d = dest;
@@ -29,6 +28,22 @@ void *memcpy(void *dest, const void *src, unsigned len)
     return dest;
 }
 
+void *memcpy_xray(void *dest, const void *src, unsigned len)
+{
+    unsigned int *d = dest;
+    const unsigned int *s = src;
+    while (len--) {
+       if (*s != 0) {
+          *d++ = *s++;
+       } else {
+          d++;
+          s++;
+       }
+    }
+ 
+    return dest;
+}
+
 int abs(int i)
 {
     return i < 0 ? -i : i;
diff --git a/part12-wgt/wgt.h b/part12-wgt/wgt.h
index e241747..5534083 100644
--- a/part12-wgt/wgt.h
+++ b/part12-wgt/wgt.h
@@ -48,6 +48,7 @@ extern short bx,by,tx,ty;
 
 void *memset(void *dest, unsigned int val, unsigned len);
 void *memcpy(void *dest, const void *src, unsigned len);
+void *memcpy_xray(void *dest, const void *src, unsigned len);
 int abs(int i);
 int strlen(const char *str);
 
diff --git a/part12-wgt/wnpblock.c b/part12-wgt/wnpblock.c
index b93d809..d40d4b5 100644
--- a/part12-wgt/wnpblock.c
+++ b/part12-wgt/wnpblock.c
@@ -3,7 +3,7 @@
 
 // We should replace this with faster version (and xray needs to do the right thing - not sure memcpy is a good replacement)
 #define fastcopy memcpy
-#define putxray memcpy
+#define putxray memcpy_xray
 
 block wnewblock (short x, short y, short x2, short y2)
 {