diff --git a/Sources/17/17.swift b/Sources/17/17.swift
index 59e6bf6..09b82ec 100644
--- a/Sources/17/17.swift
+++ b/Sources/17/17.swift
@@ -10,8 +10,8 @@ import Runner
 import Collections
 
 struct Point:Hashable {
-    let x: Int
-    let y: Int
+    var x: Int
+    var y: Int
 }
 
 struct Area {
@@ -30,24 +30,17 @@ struct Area {
     }
     
     func overshot(point: Point) -> Bool {
-        overshotX(point: point) || overshotY(point: point)
-    }
-    
-    func overshotX(point: Point) -> Bool {
-        point.x > botRight.x
-    }
-    
-    func overshotY(point: Point) -> Bool {
-        point.y < botRight.y
+        point.x > botRight.x || point.y < botRight.y
     }
 }
 
 struct Probe {
-    var position: Point
+    var position = Point(x: 0, y: 0)
     var velocity: Point
     
     mutating func move() {
-        position = Point(x: position.x + velocity.x, y: position.y + velocity.y)
+        position.x += velocity.x
+        position.y += velocity.y
         var dX: Int
         switch velocity.x {
         case _ where velocity.x < 0:
@@ -59,8 +52,8 @@ struct Probe {
         default:
             fatalError()
         }
-        velocity = Point(x: velocity.x + dX, y: velocity.y - 1)
-        
+        velocity.x += dX
+        velocity.y -= 1
     }
 }
 
@@ -82,23 +75,24 @@ class Day17: Runnable {
         
         var maxY = Int.min
         var found = Set<Point>()
-        for x in -500...500 {
+        for x in 0...500 {
             for y in -500...500 {
                 let velocity = Point(x: x, y: y)
-                var probe = Probe(position: Point(x: 0, y: 0), velocity: velocity)
+                var probe = Probe(velocity: velocity)
                 var maxYCurrent = Int.min
-                while !area.contains(point: probe.position) && !area.overshot(point: probe.position) {
+                repeat {
                     probe.move()
                     if probe.position.y > maxYCurrent {
                         maxYCurrent = probe.position.y
                     }
-                }
-                if area.contains(point: probe.position) {
-                    if maxYCurrent > maxY {
-                        maxY = maxYCurrent
+                    if area.contains(point: probe.position) {
+                        if maxYCurrent > maxY {
+                            maxY = maxYCurrent
+                        }
+                        found.insert(velocity)
+                        break
                     }
-                    found.insert(velocity)
-                }
+                } while !area.overshot(point: probe.position)
             }
         }
         print(maxY)