diff --git a/core/src/orientation/pos.rs b/core/src/orientation/pos.rs
index 566274b..28fd20a 100644
--- a/core/src/orientation/pos.rs
+++ b/core/src/orientation/pos.rs
@@ -292,6 +292,15 @@ impl UiSpan {
     pub const fn len(&self) -> Len {
         self.end - self.start
     }
+
+    /// Both ends by the same amount, which is what moving a box without
+    /// changing its length does to every part of it.
+    pub const fn translated(self, by: Len) -> Self {
+        Self {
+            start: self.start + by,
+            end: self.end + by,
+        }
+    }
 }
 
 #[repr(C)]
@@ -302,6 +311,17 @@ pub struct UiRegion {
 }
 
 impl UiRegion {
+    /// Every part of the box by the same amount on each axis. Done to the
+    /// whole region rather than an end at a time, because that is what it is
+    /// -- and because four adds in a row are four adds, where four asked for
+    /// separately are four sequences.
+    pub const fn translated(self, x: Len, y: Len) -> Self {
+        Self {
+            x: self.x.translated(x),
+            y: self.y.translated(y),
+        }
+    }
+
     pub const FULL: Self = Self {
         x: UiSpan::FULL,
         y: UiSpan::FULL,
diff --git a/core/src/ui/render_state.rs b/core/src/ui/render_state.rs
index 664e0e3..8d4c15a 100644
--- a/core/src/ui/render_state.rs
+++ b/core/src/ui/render_state.rs
@@ -1090,6 +1090,14 @@ impl RegionRemap {
     }
 
     fn apply(&self, region: UiRegion) -> UiRegion {
+        // A box that only moved carries every part of itself by the same two
+        // amounts, and that is the common move. Asking it once for the whole
+        // region is what lets it be eight adds in a row rather than four
+        // sequences with a branch each -- measured, it is where the time in a
+        // move goes.
+        if let [AxisRemap::Translate(x), AxisRemap::Translate(y)] = self.axes {
+            return region.translated(x, y);
+        }
         UiRegion {
             x: self.axes[0].apply_span(region.x),
             y: self.axes[1].apply_span(region.y),