diff --git a/day15/sol.py b/day15/sol.py
index d07f30b..1b72943 100644
--- a/day15/sol.py
+++ b/day15/sol.py
@@ -15,10 +15,35 @@ for sx,sy,bx,by in data:
     dy = abs(sy-by)
     dist = dx+dy
     y = Y-sy
-    for x in range(-dist,dist+1):
-        if abs(x)+abs(y) <= dist:
-            p = (sx+x, sy+y)
-            if p != (bx,by):
-                none.add(sx+x)
+    #for x in range(-dist,dist+1):
+    #    if abs(x)+abs(y) <= dist:
+    #        p = (sx+x, sy+y)
+    #        if p != (bx,by):
+    #            none.add(sx+x)
 
 print(len(none))
+
+# find the closest sensor to x,y within dist
+def mindist(x,y):
+    for sx,sy,bx,by in data:
+        dx = abs(sx-bx)
+        dy = abs(sy-by)
+        dist = dx+dy
+        dx = abs(x-sx)
+        dy = abs(y-sy)
+        d2 = dx+dy
+        if d2 <= dist:
+            yield dist-d2
+
+for y in range(0, 4000000+1):
+    x = 0
+    while x <= 4000000:
+        for d in mindist(x,y):
+            x += d+1
+            break
+        else:
+            print(x,y)
+            break
+    if y % 10000 == 0:
+        print(y)
+